Is there something wrong?
 

Is there anything wrong with the basic GM 502/502 shortblock for marine use (part #12568782)? I know the cam is not designed for marine, but the 502 shortblock (minus heads) can be bought fairly cheap. Is this a reasonable engine to build into a marine motor, or does the Merc/GM marine motors have different clearances, settup, etc? I know the parts are the same between marine and regular (other than the cam). The GM version even has brass freezeplugs.

Pipe up if anyone is using one......Thanks for any info.!

The 502/502 LONG BLOCK kit is fine for marine use, the specs are the same as any marine 502 except for the camshaft and the automotive oil pan.

The only reason why GM doesn't recommend the COMPLETE engine assy. 502/502 for marine use is because the aluminum heads and intake manifold will corrode in salt water (the 502/502 uses the stainless steel marine head gaskets however) and the automotive carburetor and automotive ignition are not U.S.C.G. approved. It has nothing to do with the camshaft specs.

I would say that it would be a great way to build a marine engine from scratch.

Dennis Moore

Cignificant is running a pair of 502 crate shortblocks with 250 blowers in his 35 Cafe Racer. He has had great luck with them.

Exactly the answer I was hoping for. Thanks.!