Building a new 350 SBC for my boat

So, here is the deal. 1985 Sun Runner 310 with twin VP AQ260/290As. Starboard motor is an 85 block # 14010207, probably original. Port engine is an 87 block, #10066036 (Hencho de Mexico). Replaced at some point. Looks like I will be building an engine to replace the tired low compression(90-120psi) starboard engine. The question is: Do I find/buy another 14010207 block, shortblock. Or Do I update and match the 87 10066036 engine.

Is this 87 Mexican engine a good engine? Does it belong in a boat? Once I have the old 85 block out, I can rework it and replace the 87 engine.

Also, Ricardo mentions Marine version parts. I would like to know the best recommendation for a cam profile, pistons, rings and heads. What is a good source? The engines both have original distributors on them with the sensor pickups, new Edelbrock 1409 Marine Carburetors, and they are raw water cooled.

Any advice is greatly appreciated.

Sailing aboard the Russian Princess on the Ohio River

Kevin

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Indy1k said:

So, here is the deal. 1985 Sun Runner 310 with twin VP AQ260/290As. Starboard motor is an 85 block # 14010207, probably original. Port engine is an 87 block, #10066036 (Hencho de Mexico). Replaced at some point. Looks like I will be building an engine to replace the tired low compression(90-120psi) starboard engine. The question is: Do I find/buy another 14010207 block, shortblock. Or Do I update and match the 87 10066036 engine.
Kevin, I would give this a bit more futuristic thought!

1....... Port engine is an 87 block, #10066036 (Hencho de Mexico). Replaced at some point. It may be an automotive engine..... can't say for sure!
2...... Starboard engine (as you say) is an 85 block # 14010207, probably original. It needs to be replaced!

So............
Why not custom build (or have built) a more true SBC Marine Engine for the Stbd side?
(this means using the correct piston profile, etc etc etc.) Then in the future (as the Port engine becomes tired), replace it with the same exact build!!!!


Is this 87 Mexican engine a good engine? Does it belong in a boat?
Hard to say without knowing more about the build!


Also, Ricardo mentions Marine version parts. I would like to know the best recommendation for a cam profile, pistons, rings and heads. What is a good source?
While I will not suggest part numbers to you, I will suggest that you use a Vortec style cylinder head WITH the correct piston profile that MIRRORS the Vortec quench surface.
Make a good selection that keeps you within an acceptible Static Compression Ratio.
Once you have this all sorted out, contact a good camshaft company and ask for a recommendation for Marine Cruiser use.


The engines both have original distributors on them with the sensor pickups, new Edelbrock 1409 Marine Carburetors, and they are raw water cooled.
Just an FYI........ note the potential issues with an automotive aluminum intake manifold (if that's what you are using)!

Any advice is greatly appreciated.

Click to expand...

Today we are going down to the boat. I plan on getting the serial numbers off both blocks so I know what I really have.

Ricardo, to your point, "So............
Why not custom build (or have built) a more true SBC Marine Engine for the Stbd side?
(this means using the correct piston profile, etc etc etc.) Then in the future (as the Port engine becomes tired), replace it with the same exact build!!!!"

BTW, Neither engine has an aluminum Intake manifold.

That is exactly what I was asking about. First off, I know that my engines have 2 piece rear main seals. If I go to later model engines, with one piece rear main seals, I will have to change the flywheels because the crank bolt patterns are different, yes?

Second, If I use an 85-87 block, will vortec heads work on those blocks. I didnt think they would. Do you have a recommendation on what gen block to use? I am not racing this thing.
I was going to just find a good short block, have the machine work done on it and build it up. I am not up on all the Q/E pistons or chambering on Vortec heads for Marine use. I have only built automotive SBCs and Pontiac engines. If I go to vortec heads, I also need to change my intake manifolds. What about my exhaust risers. Different too? You said you will not suggest part numbers but can you suggest sources I can read about for marine Q/E pistons and heads? I need to learn about Quench surface and acceptable static compression ratio. I thought these engines should be running around 9.5:1 From what I have read, I should be looking at 64cc heads, yes/no? Any reading that might lend itself to good sources for manufacturers of these parts?

This is starting to sound very expensive.Performance parts are expensive and then triple it when it says Marine on it. I am of a mind to just build up a stock 85-87 marine 260hp SBC and drop it in. I still will have the expense of drydocking and using the Marina services to hoist the old dismantled starboard engine out and then set the new one in place. I will do my own work. I have yet to meet anyone here that is either reputable or reasonably in priced. I really do not like paying for someone else's incompetence.

Also, we can get straight gasoline at our dock without all the additives or ethanol. Does this affect Q/E or compression or even cam specs?

Thanks for your knowledge and wisdom.

Regards,

Kevin

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Indy1K said:

First off, I know that my engines have 2 piece rear main seals.
OK.... then your Port engine would be Pre- 1987!

If I go to later model engines, with one piece rear main seals, I will have to change the flywheels because the crank bolt patterns are different, yes?
That is correct! Both the flange and the bolt pattern are quite different.
In order to purchase the correct 153 tooth ring gear flywheel, you'll need to find a '87 or later Camero std transmission flywheel.

Second, If I use an 85-87 block, will vortec heads work on those blocks. I didnt think they would. Do you have a recommendation on what gen block to use? I am not racing this thing.
Yes, the Vortec cylinder heads will fit the earlier cylinder blocks.


I was going to just find a good short block, have the machine work done on it and build it up. I am not up on all the Q/E pistons or chambering on Vortec heads for Marine use. I have only built automotive SBCs and Pontiac engines.
Doing a Q/E build is very simple and easy. Any and All machine shops will know just how to do this build. If they DO NOT.... Find another shop!!!!!!!!
A good Q/E offers great benefits for the Marine environment!

If I go to vortec heads, I also need to change my intake manifolds.
Correct!

What about my exhaust risers. Different too?
Your 1985 AQ series Volvo Penta GM V-8 does not use exhaust Risers.
You will have exhaust manifolds and elbows only!
Yes....... these will work for the new engines.


You said you will not suggest part numbers but can you suggest sources I can read about for marine Q/E pistons and heads? I need to learn about Quench surface and acceptable static compression ratio. I thought these engines should be running around 9.5:1 From what I have read, I should be looking at 64cc heads, yes/no? Any reading that might lend itself to good sources for manufacturers of these parts?

You can look right here on ME.com ....... Start reading at post #7
http://www.marineengine.com/boat-forum/showthread.php?394668-V6-to-V8-engine-swap

This is starting to sound very expensive.
The Q/E build may add about $200/300 to your cost per engine.
Machine shop labor should remain about the same as well.

Performance parts are expensive and then triple it when it says Marine on it.
These can be a good hyperuetetic LCQ style piston, and are NOT Marine specific.

I am of a mind to just build up a stock 85-87 marine 260hp SBC and drop it in.
OK.... but you'll end up with the silly GM Full Dished pistons! This piston profile should NEVER be used in a SBC Marine Engine.

Also, we can get straight gasoline at our dock without all the additives or ethanol. Does this affect Q/E or compression or even cam specs?
Yes, it may, and will most definitely affect ignition advance!

Click to expand...

Ayuh,.... I agree with what Rick is explainin',....

Goin' to Vortec heads wake up the SBC, Right where marine motors want, 'n need the torque, 'n horsepower,...

Deck the block to get 'bout .040/ .045 quench at Tdc,...
Choose the piston crown that gives ya as close to 10:1 static compression as ya can,....

No doubt the smartest way to build a SBC, unless ya stroke it out to 383,...

I started reading through the thread recommended.
http://www.marineengine.com/boat-forum/showthread.php?394668-V6-to-V8-engine-swap
Really good information. I believe "Grumpy" is referring to Bill "Grumpy" Jenkins. He was a Long Islander like me. He built pro-stock Camaros and was an expert with SBCs for the track. Not for marine use though.

Ricardo, I think you misunderstood me. To your point. I do not plan to use a standard marine SBC with dished pistons. I will follow the recommendations put forth here. I want an engine that will run reliably and perform well.

Bondo, thanks for the additional input. I will talk to my machinist and get er done right.

Regards,

Kevin

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Indy1K said:

I started reading through the thread recommended.
http://www.marineengine.com/boat-forum/showthread.php?394668-V6-to-V8-engine-swap
Really good information. I believe "Grumpy" is referring to Bill "Grumpy" Jenkins. He was a Long Islander like me. He built pro-stock Camaros and was an expert with SBCs for the track. Not for marine use though.
The guy who I was refering to in my write-up did grumpy's garage articles. Use caution when reading his articles!

Bill Jenkins (aka Bill Grumpy Jenkins) was a SBC enthusist from way back in the 60's when I was also more involved in the SBC.
Bill knew his Chit!

Ricardo, I think you misunderstood me.
I don't think so! If you purchase a long block, you almost guarentee yourself that you'll get the GM Full Dished pistons!

To your point. I do not plan to use a standard marine SBC with dished pistons. I will follow the recommendations put forth here. I want an engine that will run reliably and perform well.
Smart move!


Bondo, thanks for the additional input. I will talk to my machinist and get er done right.
If you do use the Vortec cylinder heads, pay close attention to the quench surface area and shape.
The correct LCQ style piston best suits this quench surface! (LCQ = low compression quench)
You will vary the dish volume to come up with your prefered S-C/R.

Good luck with it........ it should be a fun project!

Click to expand...

One last thing.
If I build up an 85 block #14010207 to match what is in there, and use the stock heads which should be 66cc, what is a good place to look for pistons? Anything special about decking the block?
Cam recommendations?
I want to stay with stock manifold and new 1409 edelbrock carburetor, already on.

Hey Ricardo, on a post note.
My mechanic said the coffee grinder noise on the starboard engine is not the engine, it is coming from the PDS bearings.
Good thing we are pulling that engine. the Port side will be next but it is super quiet.

Thanks for the heads up.

Kevin

Ricardo,
I just located a complete 350 SBC block casting # 3970010, serial # V0525TBC dated E27 7, not Hencho de Mexico
It is stock and will need machining and build up.
Is this a good candidate block to replace my tired starboard engine?

Thanks,

Kevin

Ayuh,... I believe that block castin' number is the most common block out there,...
A Good candidate, for Sure,....

For pistons, find hyperutectic pistons with a D-dish to mirror the Vortec heads, for maximum quench,....

This should help explain which piston profile better mirrors the Vortec and Pre-Vortec cylinder head quench surface.

Rick,
Thanks, I got that from a cross post you wrote.
I cant find you number. I know we spoke at length last year about the AQ290 outdrives. Thanks for all the help.

I just spoke to the Gentlemen with the 010 engine as quoted above. He said the 350 block is bored to .042 over according to his mic. I don't know whether it needs to go out to .060. If it does, is it still worth buying to rebuild with Hyperhueretic D-dish pistons and using the stock heads? Is .060 too much for the marine application? Or even .042 if it is a good bore?

I dont want to buy something and find out it is too tired to use.

Thanks,

Kevin

Bondo,

Thanks, I was asking for where to look for these. K&B, Pro Marine, Hastings?

Also, found out the block has been bored to .040 over. He mic'd the bores to .042. Asked Ricardo if this is too much for marine 350 or even going out to .060

Cheers,

Kevin

A .040" over or .060" over equals only .020" and .030" (respectively) of material removed from the cylinder wall.
Doesn't sound like much!
For my likings, and for a Marine build, I would not go over .040".

As for the build and part specs........ I always make my cylinder head selection first.
From there, your combustion chamber volume, plus your knowns (bore and stroke), will allow you to determine the piston dish volume.

You, or your machine shop person, can use this formula:



If you end up with a number of, say, 8.75, your compression ratio would be 8.75:1.


Or....... you can use one of the on-line Static Compression Ratio calculators.

https://www.rbracing-rsr.com/compstaticcalc.html

https://www.summitracing.com/expertadviceandnews/calcsandtools/compression-calculator



Your "knowns" are: Bore = 4.030", Stroke = 3.480"

Head gasket thickness is a compressed value. (these are available in an array of values)

**Cylinder deck height may or may not need to be adjusted. (Normal would be approx 9.025" )

Cylinder head combustion chamber volume will vary between casting numbers.

After the deck height has been verified, the chamber volume determined and the head gasket thickness decided upon............., the piston dish volume will become your means of final SC/R adjustment.


**Since we cannot go excessively "thin" on the head gasket, your machinist will be able to determine what (if any) needs to be done to the deck height in order to achieve a Quench dimension at/near .038".


Here's an example using some random numbers that I entered into a calculator:








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