Try these first:
Take a long flex handle and socket and turn engine to TDC. Rock crankshaft back and forth to measure the number of degrees of slack in timing chain, if more than 8 deg, then replace timing chain. Hook up vacuum gauge to full time intake vacuum, start engine, bring to operating temp, make sure choke is open, observe vacuum reading, should be around 14-18 ins/H20 AND steady, +/- 1 in.
Adjust dist for max vacuum, reset idle mixture screws for max vacuum may have to reset curb idle down to 700-800 rpm. Look down air horn and check to make sure there is no fuel dribbling from vacuum booster, if there is, lower fuel level on carb. Place rag over carb, does eng die? that's good no vacuum leaks. Now stand back and give a quick jab at throttle, hopefully, it'll catch and take off w/out backfiring. Check timing w/timing lite, probably find its too much for hot starting, retard timing and reset curb idle.
If carb been backfiring, you should check power valve for broken diapharm. Replace with one from book/application. If not known, then take vacuum reading and divide by 2, this will be a ballpark figure where to start. Also, install anti-backfire kit into base of carb. If possible, might even swamp distributor just to eliminate
Everett 68/359/PG 11.90/115mph