Im trying to rebuild my mercruiser gen vi 502 . I thought that these motors all came with roller cams and lifters,but my machine shop showed me that it was a regular flat tappet and single timing chain. There was a gen vi stamp on the block and one peice rear seal.Does anybody know what i have or what i buy for a cam and lifter set? thanks.

wrong forum there buddy

Roach502.
You have a Mercruiser spec engine which is probably why You don't have the roller cam. You Can get everything to convert it from Comp Cams. They should be able to outfit You with a complete kit including pushrods and valve springs.