Mike has some good advice. I had a similar issue with my 72tii. It would start normally when cold. after some city diving I would shut the car off, come back it would not start. Wait a couple of hours and it would start as normal.. Check all the basics, fuel flow, fuel pres. spark, nothing seamed amiss. Pulled plugs soaking wet. Lost trust in the car.
My son takes it out one day and this time could not get it started. Put the car in the shop, changed plugs, pertronix and coil, fuel filter. Still same problem flooding. Pull plugs and they are soaked. Got Tyler to help, did a compression test #1,2 normal, as we got to #3 dead battery. That's odd had no indication the battery was bad. Pulled it out put it on a charger o/night. Next day tried the compression test same thing. Installed a new battery started right up, set the timing and it hasn't skipped a beat.
Did some google research and there is some info on the early pertronix being battery voltage sensitive.
Hope this helps.