I have a fairly new GM crate motor, ~15k, and Im looking to squeeze a bit more power out of it. As of now, all Ive done is add a spacer to the TBI and a K&N (done a while ago). I have a Jet 6-Pack chip ready to go in. I was going to purchase Thorley ceramic headers and an Edelbrock Performer Intake for the stock setup. But now, Im thinking I might want 'new' heads and a cam upgrade (Crane Cams 'Compu-cam'). Ive searched and found info on the L31 heads, L98 heads, and the World Torquer Heads. This is what I want: I want a bit more power from the engine alone. Ill deal with the other stuff soon. I want to retain some sort of decent fuel milage (~10-15), and would like to run on 87 octane. I have octane booster for the times I want to change the chip setting. Questions: Is this possible within these perameters? Will the head upgrades cause me to have to use higher than 87 octane? Will there be quality headers available for me to use that is compliant with the emission stuff? Would you recommend not to mess with a fairly new motor that runs fine? Should I run the intake and exhaust upgradeds I originally stated and forget heads?