Backfire Runs like pure ????????

[outlaw84]

I have a Gen2 LT1 with a compression ratio it booked out at 9.8to1 64cc Heads 2.02 1.6 valves , cam Gm performance @50 218i/228E , I525/e525 1.6 rocker Hyd 112 Lobe Center roller with 100 shot nitrious (not nooked up yet) , Running 7al2 with msd pro billet 85551 dist New cap rotor wires all MSD Hot Coil Street dominator with 650 double pump 66jets frt 68 rear 65 power valve , now pulled dist rotated and locked it out set timing to 28, 32, 35 40,42,45 just fumbles on high rpm like i lose 4-5 cylinders , pulled dist , put 28 degree red bushing per msd silver and blue spring set timing at 12 ran 2500 pulled 28 degrees has quick responce ran again same crap , , came back changed 7al2 box re run same crap , change coil , same crap , put 6al on same crap , chaenged plugs and wires re adjusted valves same crap now at idle i have a pop every now and the if i rich it up it goes away Help

[Kelly Kilbourne]

Did you put the Distributor back in at 32* to 34* before top dead center or did you put it at TDC. When you lock out the dizzy you have to drop the dizzy back in before TDC to make it fire at TDC.