70k original 318 ran great then started missing and backfiring, points seemed to be going out of adjustment, re-adjusted to .017, ran well again for awhile them started running , missing backfiring but would then start running well again.

Checked wires, vac leaks, fuel, spark... replaced dizzy n intermediate shaft n bushing, coil, alt, start relay, ballast, plugs/wires, starter, 4brrl carb, intake, valve job, fuel filter, exhaust, really good tune up. Ran great, put a good 100 miles on it then started running really rough again, missing, backfiring... after a bit of that is start running well again, did that a couple times then finally limped it off the highway checked some wires, points, timing, in between starting it when it finally burned up the wrote running from the alt to the start relay up the wiring harness toward the dash. Was it a wiring issue the whole time?

Any help would be great as this is driving me insane lol