Im looking at a 91 38' Scarab with 502 mags, carbs on them....and they list the hp at 425???? is that right?
For some reason I think they sould be like 385 or something.
In any case..I think the boat should do about 65...with this stock power.
I'm thinking of throwing Pro chargers on them...which I "think" with the right props..should bring it up to about 80
Anybody have any input on this?

I'm pretty sure you're right; carburated 502's are rated at 385hp if I remember correctly. The EFI versions were rated at 415hp. Possibly a misprint?

Correct.

502 390hp at the prop had one in my boat that was 93 order through a BAJA dealer in mass I THINK IT WAS LISTED AS 425 OR 420 BOBTAIL, BUT AT THE PROP 390. ART

One thing in your favor. Those 502's are the early Mark IV Bow tie blocks. Good stuff to build on. We have done a bunch of those Scarabs if you need any help with props and specs. Smitty

That boat if its a strait hull mite run 70 with the blowers and lucky at 60 w/o them. But its a very nice riding boat.

not necessarily bowtie blocks, but still decent iron.
Rating was 410/390 (bobtail/prop).

65 gps stock is definitely dreaming for that heavy hull.

Thanks guys, thats what i thought on the HP rateings. For some reason I thought It was a stepped hull....DUH...it's a 91, no such thing..LOL
So yeah 60mph on a good day with a heavy tail wind is all your going to get from that set up. The boat is 9100lbs I believe. So even putting pro chargers on it...will only see maybe 72.