Does 500HP=?
 

Is the 500HP (1998 carbed) engine rated at 500 horsepower? I've been told it's rated at 470? Please help me get this cleared up. I even called the dealers in town and they didn't seem to know.

500hp @ crank

What he said.

If it's completely original you can assume 25 HP less!:D

Thanks all, I've been misinformed all these years... I hate that.:angry-smiley-044:

how do you figure??????

Its a 500hp engine. The bravo drive eats about 30hp.

I always thought it was 500 at the prop. So just to confirm, HP500=470 at the prop. 500EFI=470 at the prop... true?

;) I guess it would depend on the drive..but one thing is certain..its 500hp at the crank.

The confusion isn´t helped by the fact that Marc racing rates 525 and everything thereafter with PROPSHAFT horsepower - but are very hesitent to quote a crankshaft figure. The 525 propshaft hp motor produces around 560 crankshaft hp (independantly tested).

The 496 motor, like the 500, is CRANKSHAFT rated - at 425 hp, as independant tests have shown.

Crankshaft hp
496HO - 425 hp
HP500 - 500 hp
525EFi - 560 hp

Another twist in the story is that in 2000, when Merc racing was offering both the HP500 (carb) and the 500EFi motors for the APBA Factory 1 race series, they loaded the EFi boats with a 250 pound weight penalty to keep things fair (Powerboat Magazine Sept 2000).