What is the difference in a merc 5.7 or 350.

[jimh1626]

I have a P.O.S. 88 Wellcraft with a mercruiser 5.7 that says it is 350 CI. The guy sold it to me 2 months ago and after 4 outing the engine is blown. Long story short, I got screwed again. I must have a big "L" on my forhead. Anyway after trying to get machine shops to redo mine they discover 3 cracks in the block. One was welded by the guy I bought it from I guess. They say not to use it with welds. I bought another block, but it is different and I would have to replace the heads and the intake manifold. Shop said he could do it, but it also needs about $800 of machining to bore and get ready. Anyway I am looking at a rebuilt from somewhere. One place (usenginesinc.com) has a 350 and a 5.7 chevy. They list both as if there is a difference. Is there any difference? Also where is a good place to get a reliable used engine long block?

Thanks,

Jim

 

[jimh1626]

Re: What is the difference in a merc 5.7 or 350.

Never mind. I see where they say they are the same. Not sure why they would list both if they are the same, but they did.

Thanks,

Jim

 

[Don S]

Re: What is the difference in a merc 5.7 or 350.

350 Cu, in. and 5.7L are both ways of giving the displacement, one in english measurements, the other in metric.
The names can be used interchangably with the engine, but you do have to watch out for differences in the engines from year to year.
If you have a 1975 350, the block, heads, intake, etc. is going to be different than one for 2005 350.
Stick with the same vintage engine you take out, and things will fit a lot better, and be a lot less expensive.

 

[jimh1626]

Re: What is the difference in a merc 5.7 or 350.

Thanks,

Yep I am figuring that out. Where can I get a rebuilt one. Iboats??? also how do I determine the rotation? I didn't notice before I took it out. This may end up being an expensive yard ornament.

Jim

 

[Don S]

Re: What is the difference in a merc 5.7 or 350.

 

[jimh1626]

Re: What is the difference in a merc 5.7 or 350.

The engine is out and pulled apart. What can I do now as I didn't know to check.

Jim

 

[Don S]

Re: What is the difference in a merc 5.7 or 350.

a - Standard Left Rotation - All MCM Stern Drive Engines,

 

[jimh1626]

Re: What is the difference in a merc 5.7 or 350.

Thanks Don, That helps a lot. Now I don't have to wonder or take a 50/50 chance.

Jim

 

[Dryon]

Re: What is the difference in a merc 5.7 or 350.

For those interested here is the conversion factors

1 Liter = 61.02 cubic inches
1 Liter = 1000cc

 

[Hank496]

Re: What is the difference in a merc 5.7 or 350.

Mercruiser also seems to use the convention of referring to sterndrive engines using cubic inch size and inboard/ fee drive engines in metric. For example, the 8.1 liter is the vee drive package, and the 496 Mag is the sterndrive.

 

[04fxdwgi]

Re: What is the difference in a merc 5.7 or 350.

Mercruiser also seems to use the convention of referring to sterndrive engines using cubic inch size and inboard/ fee drive engines in metric. For example, the 8.1 liter is the vee drive package, and the 496 Mag is the sterndrive.

Don't know about that... My 7.4L (330 hp) is a sterndrive. I believe they ref cubic inches in the high performance engines vs: metric for the std performance motors. Just what I have observed, anyway. The Hi-Po motor would have been a 454 CI Magnum at 350-370 hp (depending on setup).