Got 98 banshee with t5, v force and port & polish. Putting on cool head with 18cc domes at 900 feet above sea level. Got a few questions,

1. What octane will i need, 91, 101, 110, and 112 are all available. Run either of the top two or mix with lower?

2. Will i need to rejet?

3.Does it make the motor run cooler. And if so any literature or web site that states this, (to prove to my uncle if true).

Thanks for your time and help!
Trent

 

I used to run 110 with klotz racing oil synthetic, with about the same mods you have, i checked the plugs and i didnt have to rejet. honestly i think those coolheads make you loose some power though, i know a cooler motor means a stronger motor, but one of the builders i know told me that

 

Cool heads loose power? WTF?

Go with 19cc domes. 18's will kill your topend RPM's. 19cc will run fine on 93 octane pump gas if you don't have any timing advance. Make sure you are jetted well.

High octane fuel doesn't give any HP and can actually hurt power unless you need it.

 

It's best to check your compression when you get it installed and see what octane you require. Using a higher octane then your engine needs, and your just burning a hole in your wallet.