The issue is ECM reprogramming. There's nobody local that I could have tune my ECM after a cam change, so I'm basically limited to stock or *really* close to stock at this point.

ok, thought the Merc 502 was just the GM crate motor 502

Sadly the cams are different. The stock 502 MPI cam is a Gm part but it's NLA.

Good to know, I have the cam that came out of my 502 MPI, but it began its life as a GM crate motor

See if it has a part# or something in nose of the cam.

-how fast do you need a cam?I have 502 mpi's sitting in my garage.I'm changing cams so these will be available.just need to know how fast you need it.

Bill

The camshaft in the picture looks like a grey cast iron camshaft that would use flat tappets. I thought that the regualr production factory roller camshafts for Gen VI were all produced with steel material not cast iron.

1622 0094 is the laser etched identifier on Gen VI MPI cam that I just sent out (1998 502 MPI).

The GM part number 12551622.

GM 502 435 hp cam.

Interesting… Merc rates at 415. To bring an old argument up, is that at the prop? Seems that 20 hp loss through the drive would align with that.

I looked online real quick for the cam. Nada. Will more than likely need to come from someone’s bin.

Supposedly, the HP discrepancy is that the black motors were rated at the prop. Blue motors rated at the crank.

And yeah, the GM part no is basically gone online. A few mentions in some forums from 10+ years ago.

Well, I'm not trying to get back on the water by next weekend or anything... I'm hoping to find a cam sometime this month. If nothing turns up obviously I might readjust the plan. Thanks!