can I put a 502 crank and rods in a 454, both are gen V. Im just looking to upgrade to forged. mercruiser shows a different part number for cranks.

I'd say as long as the mains are the same size the crank should fit. The block may need to be clearance for the counter weights though.

so, it has bigger counter weights?

They are the same. Both 4" stroke, same main size, same rod size. Both external balance.

ok, Im taking your word on it and going to install in my 454. thanks

I know my 509 Eagle crank has a bigger stroke, wasn't too sure on the 502.

PS. Where's the pictures?

Ummm you might want to check again. A 502/509/515 are typically 4.47/4.5/4.53 bore x 4" stroke, and a 454/460/468 are 4.250/4.280/4.310 x 4" stroke. So unless you did a huge over bore on a 454 with a 4.25" stroke your 509 has the same 4" stroke as a 454

The 502's have more counterweight due to the heavier pistons of a 502 bore of 4.466"

Casting number 14097044, gm forged 4" stroke 1 piece rear main crank 454/502 gen 5/6
http://www.mortec.com/cranks.htm

I stand corrected, was 99.9% positive on that one lol.