i'm looking at a boat that has twinn 502 motor's and the guy say's that they are 635 h.p. a peice .
is that to much h.p. for a 502 na. motor or is that over kill
he said i should get about 250 hour's before top end rebuild.
what do you guy's think
thank's for your help
mike

supercharged or normally aspirated?

depending on the parts inside and the rpm it is designed to run.

635HP at 5000-5200rpm is pretty easy on most parts, 635hp at 6000 is a lot tougher on everything.

If it's a NA motor then it must have some good stuff, at least ask for proof of HP and what went into motors for starters.

Oh and wait for some more opinions

carb motor
i will see the boat tommorow and ask for more info .
i just wanted to know what to ask
thank's
mike

what cam
what heads
what compression

Pistons should be forged
rods
lifters, rocker gear etc.


It's not easy to make 635 hp in a 502 without running fairly high compression and aftermarket heads with a big cam.

find out who built the motors, that will tell a lot

thank's
if they had good part's. would they be a reliable motor package.
thank's

You really need to see the verified build specs from the builder of the engines in that boat, insist on a sea trial, and a leak-down test, before writing any checks. --- Jer

If they are all good parts, probably yes. Its hard to tell good parts from the outside. If the seller can answer the questions that Wobble and I said, thans its probably true. The other way to tell is on the water test. Depending on the boat and the speed it runs. If its say a 25' Outlaw, and it runs 65, than its no where near that HP. If it runs mid to upper 70's than it probably is. (gps speed, not speedo)

EDIT: I missed the twin engine part of your post. But I think you get the idea.

thank's i am going on seatrail tommorow
33 powerplay . he say it will do low 90 mph ""92-94""
thank's

If it runs that speed, than it is probably pretty close to those power levels. Very well built heavy boat.