What heads?
 

1998 HP500 carb blue motor, can i get aluminum heads with all the right valve springs and valves that will work properly as a package.

Will original carb an intake manifold work and does anything mount off the head i should be aware of that needs to be drilled and taped or relocated.

Is the preferred heads AFR and can i get 75-100HP out of these as a bolt on? Heard of 600HP,but not sure what else might of been done?

Will the Gil manifolds bolt up ok?, Other studs or bolts required? (stainless)

Would i be able to use pump gas?

IS THIS THE MOST RELIABLE POSSIBLE 5 MPH GAIN I COULD DO?

Lot of questions,but i know you guys have the answers !

Thanks, Guys for any help or suggestions.

Randy

i used dart pro 1s on mine everything bolted up except for the dip stick.

Without a cam change and maybe an intake change, I think 75-100 HP or +5 MPH is very optimistic.

Brian,
What kind of gain did you get in rpm's an possibly mph? I only have a 24' so maybe help a little more?

Randy

100hp gain with a cam change and heads. I doubt you will gain more than 40hp without a cam change.
http://www.offshoreonly.com/classifi...o36174-en.html

Thanks, Is this using pump gas?
For $4,000 i guess the up side is more reliable than blower,i'm sure some would debate that?
With blower you only need head gaskets and redo carb? but more HP,sound right?

nope your pistons wont work with blowers.cant tell how much the heads gave me cuz i did 540s .

Call JimV (Valako Race Heads) and ask him about what heads you need. He is working on casting a marine head that will replace your stock head, reconfigure the combustion chamber to bump up the compression (no piston change), and will match his custom marine hand porting with great flow #'s. Do a search in the tech section he has done many heads for guys on OSO.
616-889-0928

I was under the impression that with whipples super charger kit specificly made for the HP500 with 6 lbs of boost you didn't have to change pistons at all?? Know mulitpule people who have installed the kit, didn't hear of them changing pistons with that package??
Unless i'm all wet which is possible.

Yes, that will be fine on pump gas.

Blower engine reliability is determined by who built them, not just because it has a blower. My hopped up 525SC with 8# of boost had 500hrs on it and was still going strong.

You could make about 650hp with a 250 roots blower at 5# of boost and a 1050cfm carb. The pistons are fine to run with a blower.
Head gaskets should be upgraded. It will be fine on 92-93 octane fuel.