MARINE ENG vs. PASSENGER CAR ENG

[MURX]

After much debate on the subject, I did some investigating, heres what I found out (350 chevy) some earlier mercruiser blocks (not all) had a higher nickel content, the marine spec Camshaft had ten thousandths more intake valve lift and held the exhaust valves open for 8 degrees additional crankshaft rotation, (some not all) 350 volvo and mercruiser engines had steel cranks (late model magnums do) So I would go ahead and use a passenger car or 4 bolt truck block without hesitation to build a marine engine, you'll need a fel pro marine gasket set and a marine ciculation water pump, brass freeze plugs and the marine spec cam if you're trying retain similar out of the hole horsepower, these cams are by no stretch of the imagination bumpy, I honsestly see a 10 to 15 horsepower increase with the mercruiser spec cam as long as you are using a marine distributor, carb, and fuel and water pumps you'll have no trouble with one of these blocks, bare in mind though if you choose a late model say '98 or '99 350 vortec there is no provision for the mechanical fuel pump and you'll need an electric pump anyone who wants the specific lift and duration cam specs you can get them from your seloc manual or go to the iskendarian website like I said the cams are hardly bumpy, I just installed a '98 350 in a searay 22'open, my buddy says he see's no difference in time to plane and a 6 mph increase in top speed, and we used the stock chevrolet truck F.I. camshaft So beleive what you want, and if you're interested you can buy a brand new 350 early casting engine from your local Chevrolet dealer and change out the gaskets and anicular components and make your own marine version of a smallblock chevy for a boaat thats going to run at relatively low rpm such as a ocean fishing boat I really don't think the extra valve lift and duration is going to make much difference if you're not shure ceck with an engine builder as far aa camshaft selection here's a link for some engines if you look carefully at this site you'll see they also have new not rebuilt chevy long blocks for 1500.00 and change http://www.rebuiltmarineengines.com/ http://www.truckengines.com/ these guys also have popular diesel engines http://www.truckengines.com/new.html

 

[Mike M2]

Re: MARINE ENG vs. PASSENGER CAR ENG

What you fail to mention are the rods and pistons. These are not the same by any means. Mercruiser uses a much sturdier rod, which is needed for the high rpms it will achieve for long periods of time. Pull apart a 260 Merc and hold a piston beside a standard 350 chevy piston, you'll see what i mean.

 

[12Footer]

Re: MARINE ENG vs. PASSENGER CAR ENG

Mike2, I agree, that a standard block would not do, but they do make the 350crate motors,which do work fine at high RPMs. The stock car folks relly on them all the time.<br />Is there a difference in these, other than the ones stated above? If so, I messed-up back in 1989,when I put a chevy 350 truck short block in my PennYan mecruiser.<br />I haven't seen that old boat on the water lately, but it ran great after the swap for the 4 years I had it. It would be interesting to see if she is still running.<br />I doubt it, given the abover info,and the number of years it has been.<br />Oh yea, and I can testify to the brass freeze plugs!!! Didn't know that back then,andhad multiple plug failures. I ended up using the rubber expandables, and they werked fine.