I broke out the firebird for the spring today (hasent been driven in 2.5 years /forums/images/graemlins/eek.gif) and was riding around town, i immediatley noticed a sever hesitation and subsequent backfiring/forums/images/graemlins/shocked.gif so i changed the plugs out for a set of #2 ac-delco rapidfire plugs and advanced the timing from 12 to 14 degrees and went out again, while the syptoms did reduce it still did hesitate and backfire. so i went to 16 degrees, and now the hesitation is almost gone but at high RPMs it backfires. not a single loud pop but many smaller pops that rob the power out from under my foot, i was just wondering if i am on the right track and what kind of an advance it is safe to go with. /forums/images/graemlins/confused.gif The motor is a 1977 350 block stroked up to 386 cubes roller rockers and a mallory unilite distributor and powermaster coil. thanks for the help. anything is appreciated.