well i think the carb is WAY to fat for the setup.....331 with stock heads/cam..with a holley 750dp and longtubes...(open headers right now) when i hold the motor and 4k rpms i hear a pinging out of the headers....the timind is 10+ running 91 octane......i wouldnt think the compression is high enough to ping running the stock heads and flat top probes but i could be wrong Anyone have an idea of what i should do? Befor 4krpms all is well. For all i know it could be something as simple as fouled plugs (havent had time to check them)