Like Dr Dirt mentioned,.. all H.O. 302's are wired the same as a 351w and dont do like I did once and wire the cap backwards. Its wired counter clockwise.

As for the missing and backfiring,.. with an air density EFI engine it could be a multitude of things.
When we picked up my wifes 87 T-top car it was hard to idle when cold kept stalling and occasionally popped back through the intake.
I had to replace every single vacuum line and hose in the car. The MAP sensor was non functional. The coil was on its last legs. The fuel filter hadnt been changed in years. The grommet for the PCV at the back of the intake was in sad shape causing another vacuum leak,.. the car was riddled with vacuum leaks and collapsed hoses, dried and hardened grommets. Bad oil leaks everywhere. The TB, EGR and IAC were choked with soot and oil. I spent the better part of a month replacing parts before the car was problem free.

Too many people think you can just jump in a 20 yr old car and just drive it like new car. You just cant do that. These cars need regular maintenance that when neglected will evolve into problems that can get costly and problematic to resolve over time. Unless you built your car from scratch and know every inch of it, they need to be looked over to find problems or find problems that havent happened yet. They are after all nothing more then a mechanical machine that wears out over time.

Hurst