Does anyone know the stock weight of the 502 mag mpi gen vi dome pistons? Im trying to match a new set that is .030 so I dont have to re-balance and the Merc part doesn't give much info on the pistons. I cant even find a part number on the piston anywheres. On the underside its stamped JE700 but as I understand it thats the forging stamp and would not yield any technical data. If I can get the part number off one (which I cant find) I could probably have JE tell me.

After pestering Smitty so much Ive learned JE makes a replacement piston at 699 grams but their .030 over piston is 714 grams. If i knew the stock piston weight Id know if ill have to re-balance. Im not in a position to weigh it as they are at the machine shop waiting on the new pistons and he's gone for the Memorial day weekend.

https://www.jepistons.com/pistons-281916 std bore

https://www.jepistons.com/pistons-281919 .030 bore

Ive read that the flywheels from a gen v 454 mag (steel forged crank) and a gen 6 502 mag are different but Merc offers the same part number for both engines. Since these are externally balanced engines I would think the piston weight differences would warrent different harmonic balancers and flywheels?

The flywheel I have is 14096805

Anyone have these in their 502? This came from a gen v 454 but since the gen vi is roller Im not sure it works right for rollers.

502s need s different bob weight on the flywheel vs a 454. I think 502s use a 27oz vs a 28oz something like that. But the Machine shop should be able to balance in the required bob weight to chamge either to the other's spec.

Balancers and flywheels should be standard balanced and not specific to the crank, so they can be replaced. If the machine shop is using the balancer and crank to balance...vs taking materail off crank...not good.

6 yr old post and he hasnt been back since he posted this,