360 trouble. please help

What RPM & how much throttle (WOT?) is it at when it acts up?. It does it from first to second & second to third or just second to third? check plugs/plug wires. need several psi at carb inlet at WOT. rotor phasing. reluctor gap (.008"). "power" timing, 35 total (checked with vac adv capped) is a good tried and true number for a SB. If you make a mark on the dampener 2&7/32" CW from the TDC slit & you want it there when the slots are maxed out (high RPM) AFTER you set your initial & I'd go with 15 BTDC & maybe 18. You will need to weld/file the slots to get it spot on. holler how it goes/progresses/any Q's What I'd do right now is set the dist so you get 35 (2&7/32") then see if that gives you enough initial to function & if so lets find the backfire then later dial in the timing perfect.