im almost out of ideas

[Branwhy]

Hi, I have a 88 c1500 that I just put a 90 5.7 TBI swap in, I changed the computer when I did the swap. Basically the engine wiring harness was all plug and play, besides a few strange plug ins that I can't see plug into anything. Anyway, I just put my exhaust on, and a new 02 sensor (pretty sure it works) and a friend gave me a new plug wire that goes to my coil, it was a bit bigger than the rest, after I put it on truck started really hard, now won't start at all, I even put my old one back on and still won't start, only rolls, I'm getting fuel and air, and pulled a spark plug and looks like I'm getting weak or lagged spark,, could I have shorted or burned out my coil, the truck did start ok before, but when you started it while it was warm it almost stalled, egr works, no plugged vacuum lines, and changed air and fuel filter, I'm out of ideas please help lol.