NVRENOUGH

After comparing these two motors on the mercruiser web site I am left with a question. what exactly is the differce between these two motors. they have almost the exact same page except for the horsepower. so what is the difference, cam? it is the only spec that they don`t list.
thanks
jason

Indy

This topic came up not too long ago. Do a search on 496 or 496HO. I think the 496HO has a forged crank, different cam, and chip is programmed differently.

Mike Shaak

I believe that the main differance is that the 375 has a cast iron crank, which I don't think is balanced. The cam is also differant,
WOT is 4400- 4800, the HO is 4600- 5000. The HO has better internals, from what info I can get. I hope this helps.

CigDaze

Check out this link from GM:
http://www.gm.com/automotive/gmpower...rine/index.htm


496 MAG (375hp)
Block: Cast Iron
Cylinder Head: Cast Iron (with exhaust valve seat inserts)
Intake Manifold: One Piece coated Cast Aluminum
Crankshaft: High-Density Nodular Iron (with undercut and rolled fillets)
Pistons: Hypereutectic Cast Aluminum
Connecting Rods: Forged 1141 SAE Steel (short -peened and magnafluxed, with 9-mm diameter connecting rod bolts.

496 MAG HO (425hp)
Block: Cast Iron
Cylinder Head: Cast Iron (with exhaust valve seat inserts)
Intake Manifold: One Piece coated Cast Aluminum
Crankshaft: Forged Steel (with undercut and rolled fillets)
Pistons: Hypereutectic Cast Aluminum
Connecting Rods: Forged 1141 SAE Steel (short -peened and magnafluxed, with 9-mm diameter connecting rod bolts.

Both are internally balanced. Besides the above, there is a different cam and programming between the two.