Can you convert a 502 MAG MPI into what I'm assuming would be a 500EFI ? A family friend is upgrading his 500HP Carb and offered me his rotating assembly, heads and cam. I would like the rotating assembly as its forged over my cast stuff and the heads and cam to pep the motor up a bit. I just don't know if the MPI would handle it or if would be cost prohibitive to have it upgraded.

Any thoughts would be appriciated

502mpi's have all forged internals already and the shortblock is virtually the same and HP500.
Heads are the same casting with different springs and might have slightly larger valves for the HP500.
The HP500 cam is not that great and has reversion issues.

The MPI will handle 500hp just fine in its stock form. You will have to have it programmed though.

Your 502 mag mpi should have dimple rods, dont be surprised to find Manley H beam rods in your buddies engine, they may have Mercury Racing printed on them, and yes both are forged rotaters...........

The Manley H-Beams started being used in the OMxxxxxxx 500EFI's. Carbed HP500's and OLxxxxxx 500EFI's had GM dimple rods.

By the book yes, but reality not always true 100% of the time....... both my 502 mpi were original to the boat in my 33OL one had dimple rods and the other had H-beam....

Strange.........Most likely some human error.