Torque loss as a percentage at any rpm will be the same as the horsepower loss, since they are related 1:1.

Michael

Great information. I'm shocked with the 60hp loss through the outdrive . Maybe my insurance will go down if I tell them my prop shaft horsepower.

That's what I heard abot the turbolators. For condensation in mid-winter climates like Michigan, Wisconsin, etc.

Hopefully great news about the 496's. Otherwise the cost of boats with a minimum of 525's standard package would jack up. Not to mention drop in re-sale value....

I guess that also goes to show that the 496ho's are not 425pshp. Ive heard people battling it out that the 496ho is 425 and the hp500 is 470 so theres not much difference.

Great Thread!

Hey Bob,
Have you ever hooked your propshaft Dyno to a 415HP/502MagMPI Bravo 1 package?
I've read that the 502Mag only makes about 400HP at the crank so that would only be about 360 @ the prop?
Thanks,

I've heard that too...that the 502 MAG was always weaker than advertised when dyno'd. I believe Merc and the other manufactures have to be within +/- 10% of the advertised HP.

Probably should leave mine in then since I live in Illinois. My steel storage shed faces Northwest and in the spring I get a ton of condensation on the boat until the ground warms up to more closely match the air temp. I love my 496 MAG and I too hope they keep the motor around.

Shooter, how did you have your elbows polished? I've got the F&M stainless motor covers, and getting the elbows polished would really make for a nice touch on these black motors.

The 496HO is 425 cshp (and ~390 pshp from Bob's testing.) The HP500 was rated 470 pshp which would put it about 517 cshp which is about where it dynos according to most sources.
Merc in the later years dropped the 470 rating...

I wish the 496HO was rated 470 cshp & 425 pshp....