Cracked 350 block 383 build to replace need input

383 Stroker Marine Stroker Build

Well I am planning out a marine 383 Stroker and I would like some input and opinions along with some guidance on cam selection. After my own bonehead maneuver I got caught and my block froze and cracked.It also blew out one of the vortec 906 heads in the process.The boat is 1999 bayliner 2655 in mint condition and the motor was too. The Motor was a 5.7 merc. With 2 barrel carb. It has a Bravo 3 2.2 geaing with 26 pitch props. Frankly I wasn’t unhappy with it’s power as I was able to pull a tube of 2 riders with 5 still on the boat. At first I was going to tear down the block,find a block, have it machined, replace rings, bearing etc and do it on thecheap, but alas finding a donor block that doesn’t need to be bored is like finding a needle in a haystack and there would be no effective quench.I then thought about doing a quench build 355 by replacing the pistons etc and having the block zero decked. I have not beenable to find effective pistons and rings that by the time I was through itwould be about $700 more than the basic rebuild. So I started looking into the 383. I read and read both in marine and street forums and this is what I have come up with. This should be around and additional $700 dollars over a quenchbuilt 355 with gobs more torque, exactly what a boat needs. To be honest I alsothought about a 454 and I have the room but I do not want the stern weight in aboat that is already plenty stern heavy.
The boat is raw water cooled and I run in fresh water however I am considering a salt water trip or 2 in the future so full marine protection is needed.
So here is my plan:
350 Roller block Cleaned, checked, Bored, honed, zero decked,brass soft plugs and cam bearings installed from machinist $560
I would use this RotatingAssembly with Flywheel with the appropriate flywheel and damper

• Crankshaft: Genuine Scat
• Crankshaft Stroke: 3.750"
• Crankshaft Material : Cast Nodular
• Journal Diameter: 350 Mains
• Rear Main Seal: 1 pc RMS
• Connecting Rods: Genuine Scat
• Connecting Rod Type: Pro-Stock I-beam with ARP Cap Screws.
• Connecting Rod Size: 6.000"
• Wrist Pin: Full Floating
• Connecting Rod Material: Forged 4340 Steel
• Pistons: Wiseco Fully Forged High Performance
• Piston Size: 4.030" (383 actual CID)
• Dome Volume: -22cc RD Dish
• Piston Material: Forged 2618 Aircraft Alloy
• Piston Rings: Mahle High Performance
• Ring Size: 1/16 1/16 3/16
• Ring Fit: Drop-In. Ready to install.
• Ring Tension: Standard
• Ring Material: Ductile Iron/Cast/Stainless/Moly
• Main Bearings: King MB557SI
• Rod Bearings: King CR807SI
• Balance: Ext. In House on CWT balancer.
• Damper: Pro-Race brand 6.75
• Flexplate: 168 tooth HD SFI Approvable, 153 tooth is available. Manual Trans. flywheels also available.

I would add in a high volume oil pump,marine gaskets, etc. I have another set of vortec heads that need a valve job that would be checked, surfaced, cleaned and valve job done for $320 at machinist. I want to keep these stock and go with a mild cam so I would be limited to below a .480 lift which I think would be fine because I am going for low and midrange torque. I would like to improve cruise efficiency and gain a little power coming out of the hole. I am not looking for top end speed and I am not a tinkerer. I want to do it once and have trouble free cruising in th eseason.
This set up running the 22cc dished pistons and being .005 in the hole should give a quench of.044 and a compression ratio of 9.209:1 which is seems high if I ever have to run 87 octane fuel which I know will happen at some time.
This is where my questions start. I amfairly certain I will need a new intake and carb. I was thinking of going with the edelbrockmarine on both with the 600 for the carb. Is there suggestions here that wouldbe similar, easy to tune and maybe a bit more expensive? Or I have the throttle body from the donor motor and the marine electric fuel pump what would it take to go to that setup and would it be better?
Next onto cam talk. I called comp cams and one of the techs suggested a couple of cams for me to meet my needs. Neither is a “marine cam” but he said should be no problem with stock, wet exhaust through the drive. He suggested xr258 hr or x4258 hr I would love input on those for marine cruiser use. Also the cam directly effects the Dynamic compression ratio which is a more accurate way of determining detonation problems and it seem to me that a dynamic compression ratio of about 7.5 is the max for 87 octane fuel. Any opinions or input on this would be greatly appreciated.

Next the 6” rods with shorter piston. I know it is preferable to go the other way around for torque purposes and shorter dwell time at tdc and bdc but is it going to be noticeable in this application or even create longevity problems.
I have searched high and low and even though this is not a cheap build I am hoping for great reliable performance under almost any conditions with longevity to boot.
And last but not least, any ideas about if I am going to have to re-prop or re-gear to improve my efficiency? If so,suggestions on which way might best fit my needs and be economically efficient. I know that is like an oxymoron in boats but hey it never hurts to try.

Wow... not sure where to start! I did recieve your PM and responded to you.

I guess first off, the cylinder block work must include the clearancing for the longer stroke crankshaft.

Next that comes to mind is the Scat Stroker Crankshaft kit. Keep in mind that the majority of these kits are being built for Street Use, not Marine use.

The Marine 377 or 383 will not benefit from the longer 6.000" connecting rods and higher wrist pin location as will the Street Engine.
Plus, this shortens the piston skirts, of which is also not desireable for the Marine build since we operate at lower RPM and heavier and more constant loads.

As for the:

Dome Volume: -22cc RD Dish pistons..... if RD represents Reverse Dome, then it's possible to use them depending on your cylinder head chamber volume.

Go to one of these Static C/R calculators, and enter your known engine data..... (bore, stroke, -22 cc piston volume, piston deck height, compressed head gasket dimension and cylinder head chamber volume, etc.) and see what this does to your Static C/R.
You mention Vortec heads. If GM, these are typically 64cc or 65cc chambers.

https://www.rbracing-rsr.com/compstaticcalc.html
or here
http://www.summitracing.com/expertadviceandnews/calcsandtools/compression-calculator
or here
http://www.gtsparkplugs.com/CompRatioCalc.html
or here
http://www.csgnetwork.com/compcalc.html

When using the 65cc chamber volume, .005" piston deck height, 22cc piston volume and a Q dimension of .044", I'm not coming up with the same static C/R numbers that you are.



Piston Material: Forged 2618 Aircraft Alloy
Piston Rings: Mahle High Performance
A good hypereutectic alloy will work as well as the Forged aluminum pistons and will be minus the expansion issues.
Perhaps also find out where the upper ring landing begins. For Marine use, we want some material here.


Flexplate: 168 tooth HD SFI Approvable, 153 tooth is available. Manual Trans. flywheels also available.
This tells me that they are thinking automotive.... not Marine.

Yes, the camshaft profile will affect the dynamic C/R. However, the quench effect is what helps against detonation potential.
Keep in mind that with a tight quench dimension (.038" or so), detonation potential is reduced, therefor the lower octane fuel may work.


As for the drive ratio.... typically when we put more torque in front of a drive, we can decrease the reduction.... (I.E., a lower numerical number)
IOW.... if this was previously a Volvo Penta 1.95:1 DP ratio, we could now use the taller 1.78:1 DP ratio.


I'm sure that there's more to cover, but this should give you a start!

It may be worth asking if perhaps Scat can accommodate a Marine build.



.

First I forgot to mention the clearancing had been included at shop and any final finishing I will do. But yes absolutly needed. As far as the kit goes I do understand and it leads me to my rather direct question of the longer rods should they be a no go in a cruiser type build? I know we actually dont benefit from them, it actually is slightly against what we are looking for but try as I may I have not been able to find a kit that is as complete and balanced as this one is that include a LCQ piston profile as this one does. All of the balanced combinatons that I have seen have the full dished piston which I will not have. I want to do anything to fght detonaion potential given the way we operate in the marine environment.

Next on compression
bore 4.03
stroke 3.75
Chamber volume 64cc
piston dish 22c
gasket thickness .039
gasket bore 4.10
deck height .005
gave me those numbers

as for the package it is put together by Skip White Performance. Def a street guy but they have had customers put them on boat wih no complaints. I had to call them on that to make sure the balancing on the flywheel would not interefere with drive connection.

forget the Hi-Vol oil pump, std pump is whats needed with the 4 Qt pan.

OK Bt Doctur wooohooo saving money already. Seriously I am having a real hard time finding a piston appropriate for good quench with the shorter rods with a dish volume that would fit my needs. Anyone have suggestions?

I am not sure why you want to build this yourself?

What are you looking at for total cost?





I would think it would be easier just to purchase one already built.

There are many marine engine builders (google) and prices are reasonable.

From what I see, a short block is about $2000.

A long block is about $3200-$4000 depending on what is used in the build.

No matter what, you will need your flywheel from your motor to be reused and rebalanced if needed. NO FLEX PLATE!!

Also I think anything under 10:1 you should be able to use pump gas. If you stay around 9.4 -9.6:1 you should be ok.

Your motor did have a knock sensor so that should help only if you use a mecruiser knock compatible ignition which your original was .

You did not mention your carb / intake set up? You will need a good intake like the RPM GAP and a 650 -750 cfm marine carb. (holley maybe barry grant)

Also you may need to get a better ignition to get the most out of a new and bigger build. The merc factory ignition for a 5.7 ltr 2 bbl will not work as well as a tunable aftermarket one. The timing curve may not be very good to get the maximum performance you seek.
Also if building this yourself you really should consider having it dyno tuned and broken in. No other way to get what you are looking for and knowing what the motor is capable of.

If you keep the merc ignition you may need to acquire one better suited for that design.......merc did have 383 motors or maybe a 454 ignition module with a different timing curve and advance rate........not sure but you need to consider this.

I fully understand the desire to build your own........But in todays world it is so much easier to buy one (with warranty) and not stress out over all the questions/details you have.

Quench, piston design, what about sign grooves? those work well.......keep any detonation in check.......

Most durable designs from what I have read simply use cast flat top pistons. No need for forged unless you feel you really want them.

Try for zero deck height, sign groove the heads, shoot for a .035" quench, adjust head gasket based on deck height to acquire the desired quench...very good mutli-angle valve job. The type of rods and pins is not so important.....like full floating vs pressed. You are not racing and you are not going to be running over 5500 rpms.......Very important to consider. A lot of the race prep and parts selection typically is based on high rpm use....

What you want is a "torque monster" not a horse power monster...........



Besides, who ever is doing the machine work/motor building should know what you need so he/they should be asked all these questions.

Asking these questions on the internet you will get 1000 different answers...........

SO more questions than answers...........go figure......

................

firel7 said:

First I forgot to mention the clearancing had been included at shop and any final finishing I will do. But yes absolutly needed.
Ah.... good call!

As far as the kit goes I do understand and it leads me to my rather direct question of the longer rods should they be a no go in a cruiser type build?
As said, the 6.000" connecting rods cause the need to raise the wrist pin up in the piston.
This shortens the effective piston skirt.
While the 6.000" rods do create less articulation at the piston connecting point, we are NOT turning High RPM as does the Automotive HP SBC 377/383.

I would stay with the 5.700" rods and lower wrist pins, giving you more skirt length.
Also, the HP Auto piston top ring landing is very close to the piston deck. This is not desireable for a Marine build, IMO.

I know we actually dont benefit from them, it actually is slightly against what we are looking for but try as I may I have not been able to find a kit that is as complete and balanced as this one is that include a LCQ piston profile as this one does. All of the balanced combinatons that I have seen have the full dished piston which I will not have.
Correct.... you DO NOT want the GM style Full Dished pistons.... especially with a 377/383 build.

I want to do anything to fght detonaion potential given the way we operate in the marine environment.
Yep!

Next on compression
bore 4.03
stroke 3.75
Chamber volume 64cc
piston dish 22c
gasket thickness .039
gasket bore 4.10
deck height .005
gave me those numbers

We were close, but my number was slightly different.

as for the package it is put together by Skip White Performance. Def a street guy but they have had customers put them on boat wih no complaints.
Average Joe customer may have had a small boat, and may not know what he could have expected.
Hard to say.

I had to call them on that to make sure the balancing on the flywheel would not interefere with drive connection.
No conflict that I can see.

Click to expand...

firel7 said:

OK Bt Doctur wooohooo saving money already.
I agree with Bt Doctur.... no need for anything but a good standard oil pump.

However, I would encourage you to go with a larger volume oil pan.... your call!

Seriously I am having a real hard time finding a piston appropriate for good quench with the shorter rods with a dish volume that would fit my needs. Anyone have suggestions?
Have you contacted a few of the major piston suppliers?

Keep in mind that with the added .270" stroke (3.750 - 3.480 = .270), the wrist pin will be higher up in the piston even with the 5.700" connecting rods.

Click to expand...

.........................

kghost said:

I am not sure why you want to build this yourself?
Jack, he may need to build one himself in order to achieve his goal.

Keep in mind that the 383 most often finds it's way into an Automotive scenario.... not Marine.
So these suppliers are most likely building HP auto engines, not necessarily Marine.
Merc, and possibly a few others, do offer the GM built 377.... but this engine uses the GM Full Dished pistons.
I would not wish that piston on an enemy!


I would think it would be easier just to purchase one already built.
Again, most all are going to be using that silly GM Full Dished piston!


There are many marine engine builders (google) and prices are reasonable. From what I see, a short block is about $2000. A long block is about $3200-$4000 depending on what is used in the build.
Would you be willing to link us to these ads?


Also I think anything under 10:1 you should be able to use pump gas. If you stay around 9.4 -9.6:1 you should be ok.
With a good tight Q/E.... I'd agree if the correct progressive ignition advance is observed.
With the GM full dished piston.... very doubtful!

Your motor did have a knock sensor so that should help only if you use a mecruiser knock compatible ignition which your original was .

You did not mention your carb / intake set up? You will need a good intake like the RPM GAP and a 650 -750 cfm marine carb. (holley maybe barry grant)
A 383 turning 4k rpm requires only 487.62 CFM.... and at 4.5K rpm, CFM is still only 548.57
Most of us are not operating our cruiser engines @ 4k or 4.5K rpm.

Also you may need to get a better ignition to get the most out of a new and bigger build. The merc factory ignition for a 5.7 ltr 2 bbl will not work as well as a tunable aftermarket one. The timing curve may not be very good to get the maximum performance you seek.
Good point.
With a Q/E build, his TA at/near 3.2K rpm can be increased some.

I hate to be quoted on this.... but perhaps this could be in the 32* range, instead of Merc's conservative 26* to 28* at/near 3.2K rpm.

It's all about getting the LPCP where it needs to be. If we're after torque..... get the LPCP near 12* to 14* ATDC.


If you keep the merc ignition you may need to acquire one better suited for that design.......merc did have 383 motors or maybe a 454 ignition module with a different timing curve and advance rate........not sure but you need to consider this.
Again..... Merc's 377 uses the GM style Full Dished piston.
Due to the increased Detonation potential of this piston, Merc's ignition system is very conservative.


I fully understand the desire to build your own........But in todays world it is so much easier to buy one (with warranty) and not stress out over all the questions/details you have.
Jack, I'll agree... but where does he find a builder who is willing to do a Marine Correct Build?

Quench, piston design, what about sign grooves? those work well.......keep any detonation in check.......
When used in conjuction with a Q/E piston, squish grooves are used in the auto world.... not sure about marine.
Keep in mind that the HP Automotive 377/383 quench dimension is more like .060" to .070", whereas the Marine quench dimension is around .038".

Most durable designs from what I have read simply use cast flat top pistons. No need for forged unless you feel you really want them.
We cannot use F/T pistons in a 3.750" stroke build with the 64cc or 65cc combustion chambers.
Static C/R would be far too high!

Try for zero deck height, sign groove the heads, shoot for a .035" quench, adjust head gasket based on deck height to acquire the desired quench...very good mutli-angle valve job. The type of rods and pins is not so important.....like full floating vs pressed. You are not racing and you are not going to be running over 5500 rpms.......Very important to consider. A lot of the race prep and parts selection typically is based on high rpm use....
Exactly! This is why these guys prefer the 6.000" rods, raised wrist pins, and shirt skirts.

What you want is a "torque monster" not a horse power monster...........



Besides, who ever is doing the machine work/motor building should know what you need so he/they should be asked all these questions.
Oh how I wish that was true!
Jack, you'd be surprised at how many good machine shop staff or owners will give their customers the "deer in the headlights" stare when Q/E is mentioned.

(see my cartoon below)

Asking these questions on the internet you will get 1000 different answers...........
Jack, that pretty much goes with anything. I too will search for info on the Internet, and I'm often disappointed with what I read or how it's been explained.
I suppose the answer is to seek the advice of those who you trust and perhaps from those who have a good track record.

Click to expand...

""You did not mention your carb / intake set up? You will need a good intake like the RPM GAP and a 650 -750 cfm marine carb. (holley maybe barry grant)""


""A 383 turning 4k rpm requires only 487.62 CFM.... and at 4.5K rpm, CFM is still only 548.57
Most of us are not operating our cruiser engines @ 4k or 4.5K rpm.""

I don't care much for carb/cfm calculatosr......they are too conservative.

It is what it is and a 383 will need at least a 600 cfm or larger no matter what. Holley has a 625 or 650 ( forget which it is) spread bore marine carb. Have installed them and they work very well on regular 350's when converting from a 2bbl.

All standard Rochesters are 750 cfm. and are variable CFM based on engine demand. The determining factor between a small cubic inch motor and a large one is a casting step that restricts the butterfly from opening all the way on small cubic inch installations. Larger motors the carb does not have the casting step. (it can be removed by hand) (of course calibrations vary greatly but that is a different discussion)

A flat top piston can be used if he uses the correct head gasket to get the right dimensions. A mutli layer stainless steel is what is needed. just get the compressed thickness right.......Say .054 to .060" (Just throwing out a number)... No issues running something like that...

I am not good with the "numbers" so I cant say what is specifically needed but it is doable.

For links just google "383 marine engines"........there are several that come up...

Again what I want to know is how much is it going to cost to build his own vs buying one already to go........?????

.

Jack, I'm not challenging you in an arguementative fashion.... I'm just wanting to continue a good and informative conversation here.
Well all learn from these threads, myself included.


.

kghost said:

I don't care much for carb/cfm calculatosr......they are too conservative.
Some will offer variable calculations depending on the volumetric efficiency % that you chose.

Summit's calculator offers

Street Carb CFM :
Racing Carb CFM :

Wallace's calculator offers

• Factory engine: 65%-75%
• Mild street performance, flat-tappet cam: 80% - 83%
• Mild street performance, roller cam: 90% - 93%
• All-out race engine, 95%-105%
• Blown engines, typically over 100% or higher, depending on amount of boost.

4 seconds flat dot com offers

CFM Required	100% VE
CFM Required	User % VE
CFM Required (Rounded)	100% VE
CFM Required (Rounded)	User % VE

A flat top piston can be used if he uses the correct head gasket to get the right dimensions. A mutli layer stainless steel is what is needed. just get the compressed thickness right....... Say .054 to .060" (Just throwing out a number)... No issues running something like that...
I am not good with the "numbers" so I cant say what is specifically needed but it is doable.
Jack, if a F/T piston (zero piston volume) is used in a build with a 3.750" stroke, 4.030" bore, .060" compressed head gasket thickness, the Static C/R comes out to be near 10.97:1.
I could never recommend that C/R for a Marine Cruiser engine!

If the valve reliefs are considered to be 2cc, it comes out to be near 10.72:1
If we increase the valve reliefs to 4cc, it comes out to be near 10.49:1
We are still excessive... yes/no?

If he went with F/T pistons and the older 76cc chamber cylinder heads, it comes out to be near 9.55:1.... but now he can't take advantage of the 65cc Vortec swirl point chambers.

I'm just not seeing how F/T pistons could be used safely with the Vortec cylinder heads in a 383 build.



For links just google "383 marine engines"........there are several that come up...
I thought that you said; "Asking these questions on the internet you will get 1000 different answers..........."

Could you please post links to these articles for him? I'd also enjoy reading them!

Again what I want to know is how much is it going to cost to build his own vs buying one already to go........?????
Show us or lead us to a builder who is NOT using the GM full dished pistons, and one who is doing a true Marine Build, and I'll be all over it!
I'll even start pointing people towards them.

Click to expand...

Spend the extra $$$ and go down to your Merc dealer. Order a 383 Stoker MPI with a three year warranty and be done with it. About 9K. You will be approaching this cost in the end.

Just pull it from the crate, drop it in, even comes full of oil. It will turn 5200 all day long.

Here's what I'm reading.

Post #1.
Jeff (the OP here) owns a 1999 bayliner 2655 .
He'd like to have more torque than what his old 5.7L would provide.
He first considered doing a 355 cu in a Q/E build.
Later he eludes to an interested in building a 383 Q/E build.
He lists parts that include a LCQ piston. (not parts that a conventional 377/383 such as what Merc provides.)

"350 Roller block Cleaned, checked, Bored, honed, zero decked,brass soft plugs and cam bearings installed from machinist $560"
What we don't yet know, is the cost of the 383 rotating assembly.


Here's the deal on the GM full dished pistons:

#1.... No Quench Effect is possible with this piston.... period!
Due to the ignition advance being held back from it's potential, the LPCP becomes lazy with this piston.
The GM full dished piston is inexpensive to produce.
One piston part number fits all 8 bores.
The guy installing the rods onto the pistons does not become confused.
The guy installing the piston/rings/rod assembly into the cylinder block aims the direction notch forward for each piston/rod.... and he's done!

All of this equates to a savings for GM.
The GM bean counters love this idea, and they won the battle with the GM engineers (who actually know better)!


Let's help him build a Q/E 383!


.

Guys, HAPPY NEW YEAR!!! And thanks for all the awesome advice and as stated, good banter back and forth will likely contribute to a better build whether everyone agrees or not. At least we will all consider other opinions or options. I thought I had mentioned I would likely be using an edelbrock marine intake and their 600 cfm marine carb. Not exactly cheap but by my calculations about the perfect fit for a 383. The way I see it a carb is nothing more than a meter or form of measure so to speak .I could put on a 750 and it would be more than enough for my purposes but just not quite as precise for“measuring” air fuel mixture. I know that is super simplified but it is the best way I can explain my thoughts on that. Am I way off base on my thinking here? This is another area I definitely need more education!!!
As far as building myself it is actually quite simple.I have looked high and low for a motor built to specs that I have outlined and I have yet to find one that is done at a price point I can afford. I can afford to build it myself though. Also it is much simpler to pay the costs as needed rather than pay the whole amount at once. 9k is way out of my league and I really see no reason I would end up near that in the end. To me that is something like when I was told it was going to cost me 175k to build my house on my property and a builder could get it done for 190k. I did it for 113k and I have all hardwood floors, oak trim and windows,and doors. Yes I had to work hard at it but I got it done, learned a lot, and saved money at the same time.
Now like the house build I needed advice and help along the way and I sought it. I am doing the same here and by my calculations I should be able to end up somewhere along $3500.Depending on costs of rotating assembly, etc. which I am trying to get a good grasp on before I spend a dime.
Now onto piston and crank selection, I have found that KBmakes a piston appropriate for that stroke with a 1.433 compression height. Those with my stock rods altered for clearance machine shop pressed on with the same scat crank as in that package and balanced with the appropriate balancer and flywheel will end upjust 150 to 200 more than that package with the appropriate flywheel etc. So it is doable to have the longer skirt pistons. Problem here I find is the selection is either a 28cc dish or 18cc both have the appropriate quench area. These sizes result in about an 8.75:1 and 9.6:1 compression ratio. Not exactly what I was hoping for but I wouldn’t mind the lower compression ratio. I could def zero deck it and hit the ideal quench. Since I am not looking for big valve lift there should be no clearance issues there. Thoughts?
Again to reiterate I am not looking to squeeze every last ounce out of this motor, more looking to improve torque over stock 350 and build in longevity. As far as time for the build if there is one good thing about living in Buffalo NY it is that we have a long cold winter and I will not miss even one cruising day during this build!!!
So I will keep looking further for appropriate rotating assemblies but between the 2 choices I have outlined so far what are the thoughts?

These sizes result in about an 8.75:1 and 9.6:1 compression ratio.

Click to expand...

Ayuh,.... Due to the detonation calming effects of the Vortec heads, the 9.6:1 is the way I'd go,.....

bondo said:

Ayuh,.... Due to the detonation calming effects of the Vortec heads, the 9.6:1 is the way I'd go,.....

Click to expand...

Bill, I would certainly agree with that, but only if his quench dimension is tight and if he uses a quench style piston… Not that silly GM piston!

The Vortec cylinder head is great when the correct style piston comes up underneath it, and offers a good quench or squish!


.

Look Here............


http://www.jegs.com/p/Blueprint-Eng...hevy-Marine-383ci-405HP-450TQ/761306/10002/-1


http://remanufactured.com/Inboard_Marine_Engines.htm


https://www.google.com/search?q=383...NsqwggTDy4DAAQ&ved=0CIUBELMY&biw=1280&bih=636

Just to list a few.........all seem to have what you are trying to build......but, all the work is done.......plug and play........

I think it will still cost you at least $5000.00 when it is all said and done........

I just took a quick look at those three sites.
None of them mention the piston profile.
I'd like to see a breakdown of specs, components and piston part numbers.

Problem here I find is the selection is either a 28cc dish or 18cc both have the appropriate quench area.

Click to expand...

Ayuh,..... I agree with ya Rick,...

It appears he's lookin' at D-dish, or inverted dome pistons, which should mirror the Vortec pattern,.....

RicardoMarine said:

I just took a quick look at those three sites.
None of them mention the piston profile.
I'd like to see a breakdown of specs, components and piston part numbers.

Click to expand...

Although the "piston profile" may be an important issue to you as evidence by how often you speak of it.

I am pretty sure that the engine builders and rebuilders/sellers know what they are doing. I am also sure that they are remanufacturing these motors to the same basic specs as OEM. Including the pistons. In most cases I would think they are upgrading components from lessons learned and new and better parts.


In the end, what they sell will work. right out of the box. If it did not I am sure it would be addressed and fixed before selling to the public.

I am also sure that a brand new OEM motor as Chris suggests will work and would be a drop in plug and play turn key installation as would any one of the motors purchased from any number of sellers.


We.....or should I say......YOU need to get past this chronic piston issue...........years on end and the same thing.

Well guess what..........if what they sell is so wrong then why do they continue to sell it? Answer........it works the way it is.

If the piston designs used on ALL of these motors is so bad as you seem to always suggest then the boating world would come to a screeching halt.

I don't see that happing so I would think what is being used works just fine.

If the piston designs used are so bad then why do they continue to use them?

Lets just agree that whatever they are using works and works for hundred of thousands of end users........as by evidence of all the boats that are in use with motors using what ever pistons the builder or OEM designers/engineers selected.

By the time one is done trying to find the perfect piston, a new complete motor whether new or rebuilt could have been installed, broken in and the boater would be enjoying his/her boat. Not wasting time searching for pistons or heads to build the "perfect" motor.

If he were building a racing motor for a racing boat this would be a different reply but he is not, nor should he be trying to nor should we be trying to advise him to..........

Oh and as he suggest he wants a 87 octane friendly motor that can push a heavy barge...........good luck.......any motor/boat from OEM that will have any performance will also have a specification most likely 91 minimum octane........it is what it is and always has been........

Only EFI motors can possibly tolerate the lower octane ratings because they are so tunable so the OEM can produce a program/map capable of dealing with poor gas blends/availability. Because he is using a carb he has to be willing to accept a need for higher octane.

Ugggggggggggggggggggggggggggggggggg

Here is a motor complete near me.......not a 383 but........

http://worcester.craigslist.org/boa/4819963074.html

Guys, I see no reason to attack anyone in particular in this thread. I asked for information, opinions and help in doing this build and I am getting that information from most of you. The way I see it everyone sees things from a different perspective and there is always value in that. Everyone's opinion matters in one way or another it is just a matter of how well each perspective meets my particular scenario. I would venture a guess that not a single one of you know for certain every single little reason I am looking at doing this build and it is not that I am hiding any but there are so many that would be an entirely different thread.

The long and short of it is I have considered a reman longblock and even a shortblock. Add my bolt ons and be done with it. simple easy fairly cheap as boat bucks go. But me being me I see room for improvement without breaking the bank. I have seen and considered that very exact 11 year old package. I thought long and hard about it but it is just that an 11 year old assembly that I am not quite sure if it is a plain and simple drop in or if there everything is in great shape. etc. Just not sure it is all worth it for me to go that way. I have also considered taking the second engine I have sitting in the garage torn down ready to me machined and rebuilt and doing it up it just needs machine work, new pistons, rings, bearings, and gaskets and I am good to go. This is still an option that is cheaper and easier and there in the event I dont see an improved build happening. It would likely last another 15 yrs or more which is likely longer than I will have this boat anyways.

I would much prefer to improve on it with something reasonably priced. 5K is out of the question period. I don't care if it is dipped in gold before I would do that I could take my second block hone it change rings clean and reassemble. Cost would be gaskets and rings and it would likely run fine for another 5 - 10 yrs. Definitely not the right way to go and IMO risky because you never know what problems might lay ahead but certainly an option.

I would like something that fits what I am looking for. I want more torque in a pocket cruiser that is used for pocket cruising, beach hopping, some towable sports. It is not an offshore racer and it is not a cruise ship either. A 383 and a 454 certainly fit that bill. A 5.7 MPI would be minor improvements in those regards but I don't know much about tuning MPI systems I know enough to know I dont know enough and would have to pay someone else to fix problems should they arise. Carbs on the other hand what I don't know I know people that certainly do and are willing to help and teach.

To top it all off, I am seeking more knowledge and guidance in making the right decisions for myself. Each of your opinions matters and contribute to my knowledge base even if myself or others don't agree. It really is that simple.

Now as far as the Q/E portion of a build. The drawbacks I have found after an exhaustive search of many different forums are as follows.
piston hitting head- typically at high rpms with a tighter quench
Not good for high boost
pain in rear to find right pistons
additional cost zero deck $130 versus $80 for resurface
pistons are about $100 more for a set but have full floating option if you would like.

Now without even looking into advancing timing for efficiency as a result. The Q/E does cool exhaust gasses faster and goes a long way in preventing detonation. Simply seems to me to be something worth at least thinking about.

Really all I want here is help in building an engine that will give me some improvement over what I had and do so at a reasonable price. I don't want to cut corners, I want to do it right so I don't miss a single day of boating opportunity here in the great white north.

So please help in that regard so this thread can move forward and I can move forward with my build.

It's best to ignore Wayne (summer fun... or whatever alias he uses).
He seldom has anything positive to add.

He is the voice of Total In-Experience!


.

Well

First off I am NOT an engine builder. Not sure anyone on here is. Most Marine mechanics fix boats not build motors. So seeking advice on the internal part selection from NON professional engine builders here most likely wont work out very well. Opinions are like a$$holes and everyone has one including me.


Have many of us put together motors? Sure we have but we use in most cases exactly what the OEM uses....why? because we are not trying to make it better just make it 100% again for the end user.

So here is my final thought on your project and I have been down this road before with this similar scenario with a larger boat and under powered motor.

1. you have a underpowered boat. It was made that way for price and price only.

2. Bravo three is the wrong drive behind a small block in a boat that large in my opinion.

3. A bravo 2 in the correct drive for a small block powered large boat. Much larger prop which moves more water.

4. The correct motor is a 454 or larger.

5. Rule of thumb for motor to boat size...

16-18 ft 4 cyl
18-20 ft v6 to v8 (5.0)
20-22 ft 5.7 to 454 low output
22- and up ft 454 - 502

Based on boat hull design then the correct drive to back it up. eg; A 26 ft cuddy with a small block should have a bravo II pushing it. Of course it should have a big block period. I have done this exchange on a 24 ft heavy cuddy that had a 5.0 alpha 1.......would not get out of its own way.
Put in a 5.7 mag (280 hp) and bravo II. Boat jumped out of the water. pulled like a raped ape for its size and weight. Done!

Not cheap and we did take the original motor and drive/transom assembly in on exchange.
Just an example of the correct way to over come exactly what you are attempting to do.

So in the end. If you want advice on engine building you need to speak with an engine building professional. In my opinion.

All you need to do is build a simple 383, good rods, good pistons (don't go over board on this), try for a good quench (harder than it seems) and shoot for 9.4-9.6 : 1 compression.
The cam will be the key for good power where you want it so choose that carefully.

Other than that don't sweat the small stuff........whom ever is doing the machine work should be able to help with parts selection and availability.

Again the OEM's use off the shelf parts and they work just fine. So if you use off the shelf parts so to will you be fine also

dont get to exotic in parts and material selection it will be a waist of time and money. besides you don't need a motor that will out last the boat.

That's my opinion..........

........................

firel7 said:

Guys, I see no reason to attack anyone in particular in this thread. I asked for information, opinions and help in doing this build and I am getting that information from most of you. The way I see it everyone sees things from a different perspective and there is always value in that. Everyone's opinion matters in one way or another it is just a matter of how well each perspective meets my particular scenario. I would venture a guess that not a single one of you know for certain every single little reason I am looking at doing this build and it is not that I am hiding any but there are so many that would be an entirely different thread.
Pay no attention to Wayne. He hasn't a clue about any of the things being discussed in this thread.


To top it all off, I am seeking more knowledge and guidance in making the right decisions for myself. Each of your opinions matters and contribute to my knowledge base even if myself or others don't agree. It really is that , simple.
Jeff, I'm not only sharing my knowledge, I'm sharing the knowledge of people such as Dennis Moore, Jeff Smith, Larry Carley, Keith Black, the guys at Crankshaftcoalition, Hot Rod magazine David Vizard, and more.
The Q/E is nothing new...... it's been used for years and years.

Look........ we will always hear from the "nah sayers". These nah sayers have no real knowledge nor experience, yet they Foo Foo this build as though they do!
This is not to bash these guys, but more so to suggest that until they gain real life experience, they simply don't have enough info regarding this build to comment negatively!

Now as far as the Q/E portion of a build. The drawbacks I have found after an exhaustive search of many different forums are as follows.
piston hitting head- typically at high rpms with a tighter quench
No worries. We DO NOT turn high RPM that would cause damage. If we did, we would increase the Q dimension.

Not good for high boost
We are not boosting incoming air with the Marine SBC.

pain in rear to find right pistons
[color=#000ff]The right people can help you.[/color]

additional cost zero deck $130 versus $80 for resurface
pistons are about $100 more for a set but have full floating option if you would like.
Find a shop who is familiar with this build.

Click to expand...

.

kghost said:

Well

First off I am NOT an engine builder.

Click to expand...

Jack, I mean no offense to you whatsoever..... but this is why the Non-Engine builder types are not actually qualified to Foo Foo the Q/E build!

Take Summer Fun, for example! I doubt that he could create a list of build specs for a kid's Popsicle Stick horse barn!

I've been building and messing around with the SBC since the mid 60's. I've built Street Performance versions and Marine versions.
I'm very fortunate that early on I learned about the benefits of the Q/E with this and other similar engines. In fact.... we didn't see GM's full dished piston until the early 70s.

To date, I have never used the GM Full Dished pistons in any of my builds, nor would I!
The Marine SBC in particular will benefit from the Q/E...... especially the 377-383.



.

kghost I do appreciate the input.

kghost said:

Well

First off I am NOT an engine builder. Not sure anyone on here is. Most Marine mechanics fix boats not build motors. So seeking advice on the internal part selection from NON professional engine builders here most likely wont work out very well. Opinions are like a$$holes and everyone has one including me.
I completely understand this and I appreciate opinions. Like I said they almost always help even if I don't completely agree I always take them into consideration so thank you for your time in giving me yours.

Have many of us put together motors? Sure we have but we use in most cases exactly what the OEM uses....why? because we are not trying to make it better just make it 100% again for the end user.
I also understand this and the financials and time involved if you were to very from it not to mention more liability exposure.

So here is my final thought on your project and I have been down this road before with this similar scenario with a larger boat and under powered motor.

1. you have a underpowered boat. It was made that way for price and price only.
Agreed although not really as bad as one might think.

2. Bravo three is the wrong drive behind a small block in a boat that large in my opinion.
Ok, good opinion please elaborate. I would hate to do this for the torque gains only to find myself held back by the drive. Changing the Drive again is not an option just too much money for a boat of this vintage IMO but a gear change or change may be in the cards. Any opinion here or ideas will certainly help me in my entire decision process.

3. A bravo 2 in the correct drive for a small block powered large boat. Much larger prop which moves more water.

4. The correct motor is a 454 or larger.
Completely agree here, exact reason I am looking at the 383. It approaches 454 torque without the added stern weight and all my bolt ons actually bolt on.

5. Rule of thumb for motor to boat size...

16-18 ft 4 cyl
18-20 ft v6 to v8 (5.0)
20-22 ft 5.7 to 454 low output
22- and up ft 454 - 502

Based on boat hull design then the correct drive to back it up. eg; A 26 ft cuddy with a small block should have a bravo II pushing it. Of course it should have a big block period. I have done this exchange on a 24 ft heavy cuddy that had a 5.0 alpha 1.......would not get out of its own way.
Put in a 5.7 mag (280 hp) and bravo II. Boat jumped out of the water. pulled like a raped ape for its size and weight. Done!

Not cheap and we did take the original motor and drive/transom assembly in on exchange.
Just an example of the correct way to over come exactly what you are attempting to do.

So in the end. If you want advice on engine building you need to speak with an engine building professional. In my opinion.
I am doing so and he gets it. But he still has opinions and they are not always 100% correct. more opinions and ideas can be helpful to even the most knowledgeable person on any subject.

All you need to do is build a simple 383, good rods, good pistons (don't go over board on this), try for a good quench (harder than it seems) and shoot for 9.4-9.6 : 1 compression.
The cam will be the key for good power where you want it so choose that carefully.
Exactly, a target that I am shooting for and when I make the selections I would like feedback on each and every choice with opinions. One of you may just catch an error in judgement either myself or the machine shop may make.

Other than that don't sweat the small stuff........whom ever is doing the machine work should be able to help with parts selection and availability.

Again the OEM's use off the shelf parts and they work just fine. So if you use off the shelf parts so to will you be fine also

dont get to exotic in parts and material selection it will be a waist of time and money. besides you don't need a motor that will out last the boat.
Again I agree, engines run for years built just the way they are, that doesn't mean they are the best option just that they do work. If I choose to vary from that I need to carefully consider how those changes effect other parts of the stock assembly is all. I do not want to get too exotic because I could easily out value the boat.

That's my opinion..........and thank you for it.

Click to expand...

Originally Posted by firel7

Guys, I see no reason to attack anyone in particular in this thread. I asked for information, opinions and help in doing this build and I am getting that information from most of you. The way I see it everyone sees things from a different perspective and there is always value in that. Everyone's opinion matters in one way or another it is just a matter of how well each perspective meets my particular scenario. I would venture a guess that not a single one of you know for certain every single little reason I am looking at doing this build and it is not that I am hiding any but there are so many that would be an entirely different thread.
Pay no attention to Wayne. He hasn't a clue about any of the things being discussed in this thread.
None paid

To top it all off, I am seeking more knowledge and guidance in making the right decisions for myself. Each of your opinions matters and contribute to my knowledge base even if myself or others don't agree. It really is that , simple.
Jeff, I'm not only sharing my knowledge, I'm sharing the knowledge of people such as Dennis Moore, Jeff Smith, Larry Carley, Keith Black, the guys at Crankshaftcoalition, Hot Rod magazine David Vizard, and more.
The Q/E is nothing new...... it's been used for years and years.
I understand and have looked here also.

Look........ we will always hear from the "nah sayers". These nah sayers have no real knowledge nor experience, yet they Foo Foo this build as though they do!
This is not to bash these guys, but more so to suggest that until they gain real life experience, they simply don't have enough info regarding this build to comment negatively!

Now as far as the Q/E portion of a build. The drawbacks I have found after an exhaustive search of many different forums are as follows.
piston hitting head- typically at high rpms with a tighter quench
No worries. We DO NOT turn high RPM that would cause damage. If we did, we would increase the Q dimension.


Knew this and even High RPM guys consider .035-.040 to be the safe range.
Not good for high boost
We are not boosting incoming air with the Marine SBC.
Nope, naturally aspirated

pain in rear to find right pistons
[COLOR=#000ff]The right people can help you.[/COLOR]
Found

additional cost zero deck $130 versus $80 for resurface
pistons are about $100 more for a set but have full floating option if you would like.
Find a shop who is familiar with this build.
The guy I have found is best and most used in area for boats. He does understand it and even wants to do his own for his 23' cuddy but he is a car guy world renowned for his LS1 work. I don't want to ship out for machine work increasing costs to the build if not needed when he is completely familiar with that. Just want my own backup information so he or I do not make an error in judgement.

I have found that even engine builders are very careful who they discuss Q/E builds with at least in the SBC realm. They seem to need to be prodded to go there and only after I bring it up and show a little knowledge about its background do they start to spill knowledge. I guess they are afraid to risk liability exposure from it if someone were to do something completely stupid and blame them, or they don't want to be bothered to explain it fully because it does take some understanding. Bottom line I have found is that you cannot go to any performance forum without seeing quench discussed as if it is and every day thing.

Again I appreciate your help and look forward to getting this thing specked out with all of your help.

Summer Fun II said:

I don't know who that Wayne guy is but.... You sit in your trailer and type bullsh*t

Please answer my questions. Have YOU ever built or used one ?. I'm saying NO you haven't !.



You came up with this hairbrain idea of using it in marine engines.

You got shot down by DonS and Others over this Q/E nonsense on BOC & iBoats.

Click to expand...

You've been banned in most every boatin' forum on the net,...

Crawl back into yer hole, 'n stay there, Troll,....

Thank you, Bill. Well said!

Perhaps we can now get back on task here.




.