ok, when i hit the highway, ...and do a long rpm haul, say from 60 - 100mph in drive....after i let off the gas i get a loud backfire through the tail pipes, ive tried ALL timing advances, ....0 2 4 6 8 10 12 ......so someone said i might be running lean.....i have no power loss what so ever, it just backfires after high rpm revs or long rpm hauls.....lets say from 2k to 5500k ....POP heh....i recently installed a lt1 cam....jus in case anyone needs to know