i put a set of dart pro1 heads with 1.6 roller rockers on my 327, after i fired it up it sounded great but when i took it to the streets i punched the gas and around 4,000 RPM it would start backfiring through the intake like crazy. ive heard it could be a worn lobe but it didnt do that before, and ive also heard it could be timing, fuel pressure, coil, even my brand new valvesprings could be broken. any input would be helpful thanx
