1991 Chevy Camaro ignition timing(I think)

Whats up guys, I did a swap on my 91 Camaro. I put in a rebuilt 1973 350 4 barrel converted to TBI. Ive modified a 91' tbi manifold to fit the older heads and changed the needed sensors, injectors, fuel pump, and ECM. Before I put it in, I installed a Comp Cam, full exhaust from header back, tbi spacer, 8mm cables, MSD coil cap and rotor. Before I pulled the stock cam out, I set to tdc on #1 and proceeded with the install. Well I put the engine in, reconfigured my distributor and cables and started it. Now ive been messing with it since I got it in like 2 months ago and I still cant get a consistant(500-750rpm) idle with out it stalling out. I have to keep giving it gas to stay on. Also, once driving lets say I need to speed up. If im in 4th to 3rd, drop the gear and give it gas it hesitates. Sometimes on take off as well, if I rev it up passed 35k it hesitates. My guess, since the ignition cables wer used before on the original engine, they might have weak points on them from touching the hot exhaust. Could it be a spark leak or the same ignition timing issue? Sory for long blogs but if you need help, you need to go to the pros. Thanks for the help! Oh yeah I have no check engine light goin off or no codes coming up, thanks!