[buchshot12000]

And I found a 4 inch crack spanning between the middle cylinders on both sides
I have a 5.7L out of a truck. Are the heads the same? or do I need to pray that the heads are still good.

[darkcalling]

What year is your boat and the truck engine if they are both none vortec they will work if they are both vortec they will work.

[buchshot12000]

Originally Posted by darkcalling

What year is your boat and the truck engine if they are both none vortec they will work if they are both vortec they will work.

the boat is a 95, and the truck is older then that late 80's early 90's, if my heads are toast can I use the truck heads?

[buchshot12000]

Well it looks like I wont be able to salvage much from this engine I still need to pull heads I got discouraged after seeing this and decided to have some whiskey.

The white spot is what i found under the thermostat. To bad its its the cooler under neath.
Hopefully i can salvage the manifolds.

[darkcalling]

95 the vortec heads were a late year option most likely would have worked

[ShabahZ280]

Marine engines and truck engines are different. Do yourself a favor, for your own safety use a marine engine. While they may seem the same, marine engines are engineered specifically for the marine environment to withstand water, salt, and eliminate any potential hazards in the boat. Spend the money and do it right. All it takes is one spark and your boat's toast (and possibly even your passengers and yourself too).

[buchshot12000]

Originally Posted by ShabahZ250

Marine engines and truck engines are different. Do yourself a favor, for your own safety use a marine engine. While they may seem the same, marine engines are engineered specifically for the marine environment to withstand water, salt, and eliminate any potential hazards in the boat. Spend the money and do it right. All it takes is one spark and your boat's toast (and possibly even your passengers and yourself too).

I have been talking to a machine shop about that. If I can salvage the heads the only thing that will not be marine is the block, and maybe heads. all other components will be marine, but it will built to handle it.

[darkcalling]

Not to question Shabah or even disagree his boat knowledge is far greater then mine I assure anyone reading. I did check with GM and Mercruiheser before I went and did my sbc up on my old boat which has been running perfectly with usual maintenance for 12years now. The both sources at each company and both with over 20 years at each said the blocks and heads of gm performance and heavy duty applications were the same. I did use marine external parts ;starter and alt so forth.
Being I run only in fresh water and basically two lakes, I did switch to aluminum heads and exhaust and intake manifolds, not an option if you run in salt though.

[DougR]

We had a bad block this winter on our 2003 5.0 (impeller failed) and here's some of what I discovered gm makes mercs engines nothing different in fact ours was only a two bolt main (the old head production numbers crossed over to a GMC truck motor). However, merc does use an epoxy paint and we used that on our engine to help give the new cast iron a chance I converted the oil pan and installed the old roller cam in the new block (Some other major things we added or changed marine gaskets, marine oil splash plate and the motor had brass freeze plugs).

Doug.