Best Fatheads for higher overdrive

Looking to step up to a newer set of heads with a roots blower. Interested what would be the cylinder head of choice for a higher overdrive, 40%+.

Thanks-

 

What RPM?

Are you asking at higher RPM? or lower, and where to you want to make power? THANKS! Jim

 

It would be in a boat, rpms would be on the low side. 9000 would be about the max and around 7500 when the prop hooks up.

 

heads

I wouldn't be surprised if a 481x could dominate that application.

 

1/4miller,

I would start looking for a screw blower because 40% overdrive is about the limit for a roots. What kind of boost are you getting with your blower?
Joe

 

The class I want to run is limited to roots superchargers but has a high OD limited. We already have some BAE parts that we acquired so that will be the direction we will head. I just wanted to see if anyone had a preference on alcohol cylinder heads for a higher overdrive roots application.

 

Bae

Any fathead will work good enough to set records in a boat.only about 150hp from 5 to 8x. The blower will make a lot more difference. Ihra funny car ran roots at 55%. Those blowers were the last real effort I know of for high over drives.

 

Blower

The New SSI blower is awesome and comes fully modded for an excellent price, run it at just over 40 percent and blend it to a good hat to make great power, at that rpm the rotor tips shouldn't go supersonic so you should be good.

Anything Brad 5 or Later will work good as long as rules don't affect valve sizes.

Hope that helps a little,
Trevor Sherwood
727-364-4368

 

If you have a data logger the boost graph will tell you if you are spinning the blower to fast or not fast enough .

 

Remember that BAE 7 - 8 take different headers.

 

Pizza set the previous top alcohol hydro record with BAE 6's with a 4.4X @ 1,000' (C case screw blower). And the current 4.32 record is with 8's. We run 5's on our PM drag boat deal and they work great.

Shannon