spent 4 hours chasing a bad breakup from about 3000rpms and up....tried a difernt msd box, plugs, gap, coil,indexed distributor....finally tried pulling timing...almost 20 degrees and it cleaned up....really weird...had to have 20 deg of timing for it to run clean(really weird)....made some pulls at 10psi...motor was breaking up again at 5500...made 650rwhp at 5500....motor should keep pulling till 6800-7000....at 10pm the cops showed up so we had to call it a night...going to swap out the plugs tomorrow with a wider gap (had the gap at about .012 to try and figure out if it was a weak ignition).....definetly was some weird stuff going on.