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Differences between volvoGM 305350cid engines

R

realslimshady

Contributing Member
"Can anyone give me a definiti

"Can anyone give me a definitive reply whether the physical differences between these two capacity engines is restricted only to the cylinder bore? Put simply, can I remove a 5.0l (305) and bolt a 5.7l (350) straight in its place, with things like flywheel, inlet and exhaust manifolds, mountings and distributor all dropping straight on? Thanks in advance.
Martin"
 
"Other than bore and stroke th

"Other than bore and stroke there are no differences between the small block chevys. In other words, the external dimensions of the 305 and 350 are identical.

That's my story, and I'm sticking to it.
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"
 
"I'll second what Eduardo

"I'll second what Eduardo just said. If the year model is same, most of these parts will interchange. The Harmonic Balancer on some are a different size.

If the year differs (in/around pre'86- post'87), the crankshaft flange changes (different flywheels).
The intake manifold bolt angle changes in/around there aslo. This changes again with the Vortec.

Sounds as though you are gearing up for a possible 5.0L replacement with a 5.7L!

."
 
"Ah...better check what year t

"Ah...better check what year the possible replacement engine is...
Yes,need to change the AQ200D in my boat-submerging it earlier this year didn't do it any good, and the compression was already dodgy on one cylinder,valves have seized in the heads again...basically, it needs a complete refurb,if it's recoverable..so looking at replacing it complete, and there is a 5.7 on ebay looking like a bargain. Better check the year tho!"
 
"Most of the post 87 small blo

"Most of the post 87 small block Chevs the 14" flywheel, but 12.75" flywheels with the new flange/ bolt pattern are available. No biggie. I would also expect that the new engine comes with the intake manifold installed. Something like this.

http://bpi.ebasicpower.com/engines/base/350.htm

If you choose to have a 14" flywheel, you will need a different starter and a different bellhousing; so if yours are in good order, a 12.75" flywheel would be your cheapest option.

Alternatively, you can always get a rebuilt long block of the same vintage as yours."
 
"My situation is that the 5.0l

"My situation is that the 5.0litre in the boat is no good. Could remove and have overhauled, but cost is prohibitive. 5.7litre is on ebay cheap...but seller doesn't know what year...think I'm going to pull my engine first, then see what else has arrived on the market. As for your link above, El P-if only I lived in the states...."
 
"I am uncertain of what this w

"I am uncertain of what this would be like in the UK...... but Yes.... fully agree that over-hauling a 5.0L is cost prohibitive in-that you can often do a 5.7L for less...... at least here in the US.

Most all of these replacement engines are using the small chamber heads and dished pistons. If your hull is of any size (26ft + or so), you may want to have an engine built for you and get away from this configuration.... for a true marine SBC, that is!
The dished piston/small chamber heads is not ideal for a SBC Marine Engine. These really require a Q/E.... (quench effect) cylinder configuration to perform well and to help eliminate potential detonation isues.

Dennis Moore's "Small Block Chevy Marine Performance" offers a lot of good information on building a proper SBC Marine engine.

As for the e-Bay seller.... if the 5.7L engine is 1987 or later, it will have the center bolt valve covers, one pc rear main seal, and the size (in liters) will be raised in the casting @ Port side/rear.
Otherwise, you'll need to determine by serial number.

If you have the older one pc exhaust mans, the later engine center bolt valve covers work much better.

FYI: note that the Vortec intake manifold sits higher, sometimes preventing an engine hatch from closing.

The 153 tooth flywheel for the later crankshafts can be found. It's actually a 5.0L Camaro stnd transmission application.


I'd strongly encourage you to replace the PDS bearings in your flywheel cover. Cheap to do, as these are a standard open bearing that can be found easily! It'll be good insurance against failure down the road!

Since this is likely an older boat, you will have a fair amount of un-tinned copper wiring in it! If she was under in salt water, you are in for some future issues with any wiring that became wet. Be prepared!

Good luck.... post back with any other questions."
 
"Thanks for all that info Rica

"Thanks for all that info Ricardo-just to clarify-an easy way of 'dating' the engine is the rocker cover bolts?
Yes, she's an old boat, and not worth spending loads of money on...but worth next to nothing without a functioning engine! It's trying to find a balance between what you spend and what it's ultimately worth..."
 
"Hey, I know all about being u

"Hey, I know all about being upside down in an older boat! Ya just use it up in the form of enjoyment!

Answer: NO, not entirely!
It will give you an idea of which category it falls into.... pre '86 for the 5.7L .... and pre '87 on the 5.0L 2 pc rear main seal. (I may have that reversed) After '87, all were one pc rear main seals and center bolt valve covers.
Then things change again, but all continued with the one pc seal and center bolt V/C's.

There is a little more to it re; intake manifold, etc."
 
"RE:" upside down in an ol

"RE:" upside down in an older boat"

Actually you are usually upside down in a boat before you get it home, especially if new! Soooo... you better like it and enjoy it...

//from someone with a 1969 23' power boat AND a 1972 22'sailboat....both bought "at the right price" :)"
 
"Your [b]Flywheel Cover[/b] &#

"Your Flywheel Cover (bell housing in the auto world) will work on any of the SBC marine engines..... it is not year specific!
The Flywheel is year specific..... and must be the 153 tooth ring gear for this AQ series flywheel cover..., like I mentioned earlier! (it is the 168 tooth that will NOT fit within this flywheel cover! )



Just an FYI re; these two engines in Ireland:
Yes.... these are early engines (pre-1986-7)..... perimeter valve cover bolts/2 pc rear main seal. A non-issue actually.

The Bendix type starter motor would not do for me.... Very old technology for today.

Older Prestolite ignition distributors.... No on them!

They have been raw water cooled during this 300 hour previous life.... that may make a difference to you... it would me!

Am I seeing a bronze bushing in the ends of the crankshafts????? (for you marine engine guys, that may be a red flag)

Quote: <font color=""0000ff"">If the power is not big enough for you the engines can be tweaked up from the 225hp to 280hp.</font>
I hope that you realize that this is not true.


They appear to have been well taken care of, and/or very nicely re-painted.
They are presenting these very nicely as the ad is shows well!
They include much of what a person would need for a re-power under the guise that all is good!


Ad says; <font color=""0000ff"">USD $3,244.12 Approximate US Dollar Equivalent.</font>
Now calculate the cost or value for good used; <u>exhaust manifolds, a flywheel, an intake and carburetor, a distributor and a circulation pump!</u>
Subtract this sum from the asking price...., and that is what you would be paying for this "re-manufactured" engine.
<u>This may not be a bargain for a re-man 5.0L..... I don't know your market!</u>
Being a little on the skeptical side..... just what is "re-manufactured" to these people?


You may want to contact Roger at MichiganMoroz.com
Currently, they are offering a 5.7L (350 ci) marine engine (1967-1985) Long Block w/ tin ware, for US$1,999.00 and a One Year (parts and labor) Written Warranty.
These people have a great reputation.

http://www.michiganmotorz.com/Marine+Engines/Remanufactured+marine+engines/5.7L+ %28350+ci%29+marine+engine+%281967-1985%29




This is a repeat since you did not respond to it: I'd strongly encourage you to replace the PDS bearings in your flywheel cover. Cheap to do, as these are a standard open bearing that can be found easily! It'll be good insurance against failure down the road!

OH.... What boat is this engine being installed in? Type/length/style, etc???? Just curious as I am sure the other guys are! "
 
"Ricardo
re the pds bearing,

"Ricardo
re the pds bearing, don't worry-it's on my to-do list!I'm fairly sure it's shot anyway, was making horrible noises on any kind of steering lock.
The issues you raise above-starter motor? Identical to the one on mine, which I just resurrected after its submersion, and works happily, so that makes one spare.
Distributor? Have fitted electronic ignition to mine, so a straight swap.
Raw water cooling? Seems a pretty common way of doing it....
And-please stop quoting me the prices you guys get to pay in the states!! It hurts!!!!
Not worried about the power increase quoted-225 will be more than plenty-boat is a Fairline Weekender 22'.
Thanks again for sharing your knowledge.
Martin"
 
"bit more help guys?
got the

"bit more help guys?
got the flywheel cover in the workshop to change the pds bearings-any tips on getting them out?
Have removed the oil seal and snap ring from the forward bearing, am struggling with the rear seal at present-am I right in thinking that there is a lock ring on the rear of the shaft stopping me driving the shaft forward out of the casing (bringing the forward bearing with it)?
And why are there two snap rings on the rear bearing (according to the drawing)?
Cheers!"
 
"
Be careful.... do not star

"
Be careful.... do not start driving on things until you understand the PDS, bearings and retainer clips (snap rings).

The PDS comes out AFT.... ALWAYS!
With the seal out of your way, remove the two large expansion type snap rings from AFT.
(the best tool for this is a looooooong needle nose pliers with the tips modified to accommodate the eyelets of the snap ring.... there is no better tool, IMO.)

With a brass tool, drive the shaft out AFT ONLY!
This leaves the FWD bearing in place.

After the FWD snap ring is removed, the FWD bearing is then driven out FWD from an AFT access.

The AFT PDS bearing is held onto the PDS via a small compression type snap ring.
Remove that, and the bearing is now free to be removed from the PDS.
(This is a generic bearing p/n 6206 in anything but a Chineese bearing
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)

Install in exact reverse order.

Prime the grease cavity completely (as you spin the shaft) until you see grease come through the ball cage of the aft bearing.
At this time ONLY, do you install the seals.
(use a good high pressure bearing grease... not green marine grease)

The seals are best installed if a sealer is used to help hold them in place.... particularly the FWD seal.
If blown out by too much future grease, this forward seal will breach any pressure required for future grease to the AFT most bearing! (very important!)
In fact.... I hate to see the AFT seal do a good job of sealing. It need not under the guise that we will always keep good drive bellows installed!
IOW's, you do not want the AFT seal to outperform the FWD seal !!!!!!

Just make sure that the FWD seal is somewhat sealed/glued in place! You'll be OK.


FYI: Future greasing should be done w/ engine at idle. (dynamic vs static)
"
 
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