Dissapointing performance

better heads? These flow 270 cfm and are high velocity heads. I thought that these are best heads what you can buy for street use.

I was making reference to the upgrades you did. New (better) heads and cam. On advancing the cam, yes it can cause detonation. That's why the timing is important. Advancing it will help build more cylinder pressure which will help the low end. My last three engines have had the cams advanced four degrees, 102,103 and 104°.

BTW the intake you have is fine.