I thing both these motors have similar horsepower. I'm looking at mostly equivalent Formula 370's a 2001 and a 2002. Is one motor better than the other in this application. Thanks for any input.

Never owned a 502 MPI, but, I've owned a 454 Mag MPI and a 496HO. The plus of the 496 is closed cooling, and smartcraft capability. I can't think of any cons, except if you plan on modifying the 496.

502mpi has better internal parts.

496 has closed cooling and is a higher tech engine with more things being controlled by the PCM.

Both good motors. Similar in design and performance. 496 HO is 425 hp.

496 does well on low end torque but is a dog on the top end. The 502 seems better on the top end. IMO depending on boat / hull I would go with a 502. People are going to say the 502 MPI is so outdated but I know people will disagree with me hear but the 496 is outdated as well. Down the road 496 parts will be harder to get and currently less and less marine mechanics do not even want to touch them especially twin apps. The marine sector was the biggest sale for the GM 496 -- with that said It still was too small of a market for GM.

If left stock they are both great, reliable engines. If you plan on modding then the 502 is better as it has forged internals.

Probably would not mod other than I would want to add closed cooling to the 502. Not sure how involved that is but I looked at a 400ss in Virginia that had new 502's with closed cooling. I'm in salt water