I am installing a stock-bore, 11:1 Wiseco piston, and an XR400 cam on the 17th. I don't know what to run for gas. I've heard all kinds of octane numbers. What is suggested? I haven't asked my engine builder yet, so I thought I'd take some time and see what you guys suggest. I don't want to run a higher octane fuel than I need. For example, if all that was required is say, 100 octane, I wouldn't want to run 110. I do want everything to hold up though. Please help. Thanks.

 

I've been running premium pump gas for a year now and i am running 11.25:1 compression on mine. I haven't had any problems at all and no pinging. I think as long as you are going with a higher duration cam, premium pump gas should be fine for you too. when i ordered my piston, CT Racing recommended 100 octane for my c/r. So when i put the piston and cam in, i started using 105 octane. that was fine, so then i mixed premium pump and 105 race gas half and half to get about 98 octane. No pinging, so then i tried premium pump gas mixed with some octane booster. Still no pinging, so then i went with straight premium pump gas and it was still ok. So if i were you, i would start out with 100 octane and work your way down, it's better to be safe than sorry.