Call WhiteBrothers racing they can help you. Although they can be a$$ holes sometimes. They know there stuff.

 

why you just jumping to a 440? i personally would get a 416 with a nice cam if you dont' want to spend too much cash. a 416 with a cam will out run a 440 any day of the week if it just has a piston in it. the 440's produce a lot of heat too.

 

The traditional rule of thumb is to divide the available octane by 10. As you go above that ratio you have increasing issues with detonation, heat, starting, .. These issues are addressed with swirl patterns on the piston crown and/or head, ignition profiles, etc. etc. Whatever piston you get, make sure you ask what octane that particular design needs. It will vary by compression ratio and piston crown shape.

Back when Sunoco used to advertise that their lowest grade of gas was 100 octane, milling heads and high compressions were an easy way to get HP. Today's regular at 87 octane is equivalent to the old Gulftane. The only engine that would run on Gulftane were the old 6volt VW bugs with 7:1 compression ratio engines. I thought it was great when I found Gulftane for my old bug because I saved a whopping 2 cents a gallon compared to regular which was a horrible 19 cents a gallon.

 

I was told when doing my Big Bore ( I have a 426) that no race fuel is needed for this comp in mine and will actually run a bit better w/o. Unless your changing the timing curve then you may detonate (like we done to the Predator with a Vortex CDI we have ro run 60/40 C12)race gas isnt needed. I have heard no pinging with mine and runs like a champ. These reccomendations came from 3 major Racing Companies. Tina

 

Call Rich at Hetricksracing. He is a whiz when it comes to the Ex........[img]i/expressions/face-icon-small-wink.gif[/img]

 

Actually wiseco are much closer to advertised. JE pistons usually actually run high.

 

Isnt JE and Ross about the same? I thought I read that somewhere......

 

no, the ross pistons are closer to the actual compression as well. a 12:1 je is actually about a 13.3:1. 11:1 is about a 12.4 or something.

Craycraft just switched to ross pistons in their 686 raptor big bore kits. They say they are much stronger.

 

So Far Im happy with my Ross piston.....[img]i/expressions/face-icon-small-smile.gif[/img]

 

I am the first 686 with the Ross Piston. I'm sending my parts to Bob Monday. So I will be the first 686 Craycraft this is based around the Ross Piston. Yay for me!!!