Mercruiser 5.7 rebuild

I just got my hands on a 5.7 GM marine short block as my mercruiser 260 just cracked the block. I am planning on doing a full rebuild top and bottom end on this new block. I cant seem to find any rebuild kits that are specifically for a marine engine. Will just a regular chevy 350 engine rebuild kit work (pistons, bearings, etc.)? I am planning on using all the external items from my old engine onto this one.

If you are wanting to go a bit beyond the average GM SBC Marine style build, give this thread a read starting at post #7.

http://www.marineengine.com/boat-forum/showthread.php?394668-V6-to-V8-engine-swap


You'll end up with a more suitable Marine build.




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You will spend more in time, labor and parts on this than you would buying a refurbished engine. A reconditioned marine engine is about 1800. Comes with warranty. Really hard to beat that.
You can find nice marine engine rebuild kits on ebay. Dunno what you paid for the lump but if you buy this kit, along with the donor, plus machine shop work, plus balancing and assembly you are at least at or above the same cost as turn key. Your time and labor not added to this of course but if you did have to pay yourself, what would you charge you for this job?

o2batsea said:

You will spend more in time, labor and parts on this than you would buying a refurbished engine. A reconditioned marine engine is about 1800. Comes with warranty. Really hard to beat that.
You can find nice marine engine rebuild kits on ebay. Dunno what you paid for the lump but if you buy this kit, along with the donor, plus machine shop work, plus balancing and assembly you are at least at or above the same cost as turn key. Your time and labor not added to this of course but if you did have to pay yourself, what would you charge you for this job?

Click to expand...

Absolutely the way to go.

But if you insist, based on year of block.
Any short block rebuild kit will work.
Only marine issues are core plugs need to be brass/stainless steel not steel.
You will to swap your original oil pump, windage tray, and oil pan, flywheel, water circulating pump, intake manifold and carb maybe timing cover maybe not.

Get good head/piston combo, you can bump up the cam a bit if you want.....high torque at lower rpms...

Marine gasket kit and the simply swap all accesories.

If you know of a good engine build shop simply speak to them for advice and cost.

If your just redoing a stock replacement and reusing your original heads.....go by year/casting number and order parts accordingly.

the standard marine 350 260 hp is a truck block.
Some are 2 bolt some are 4 bolt.

I got the short block for free and I am on a tight budget. I found some kits on amazon for $250 including the auto gaskets. Should I disregard these auto gaskets that it comes with and get the marine ones? Is it bad to run regular auto gaskets? first time dealing with a boat engine so unfamiliar.

The Key gasket is the head gasket. It cannot be stamped steel. It needs to be marine grade and or stainless steel.
Raw water not antifreeze mix passes thru it and if stamped steel it will rust away quickly

Intake and exhaust make no real difference.
Oil pan may be different and you may have to get it from this site or a marine store. As you will be romoving oil pan, make sure what gasket is available in standard engine kit vs what is on marine engine now.

Most marine oil pan gaskets are one piece and typically rubber not always cork.

On the front and rear of block/intake on sbc they suppy a Z cork gasket.
Dont use.
Use high quality rtv and put a solid 3/8 " thick bead from intake gasket tab to tab, front and back surface. There is a grey high strength rtv when hardens it is harder than normal rtv. Look for that.

Thanks kghost. My current engine is a 1986 260/v8. The engine I just recently picked up is a Will everything be able to swap over or will I need to purchase new heads, intake, accessories, etc.? Obviously the internals I will order specific to that engine, even though I ASSUME that all 350 5.7 internals are the same?

Two different engines.
The 86 is two piece rear main seal, different coupler attached ro flywheel,
Possibly different flywheel.

Definately different heads and intake....the new is most likelyva Votec block and ahould have appropriate heads.

I am not a parts exchange wizard for a older to newer engine.
Maybe someone else is....

But many differences between the two for sure.

Also I am on my phone here so have no acess to any resources.

Maybe start new thread,
Differences between 86 and 96 marine 350 sbc.

Yup now you have a block that almost nothing from the old engine fits to. Exhaust manifolds I guess. Carb probably....