[Lady72nRob71]

New'n72,

Did you ever get this resolved?? I found this thread rather late...
Lady (my '72) has your exact same problem. In cold weather it is better, in hot it is worse.
My suggestions that I will undertake when it gets warmer out:

1-replace fuel filter (I heard some of them may have a check valve in them to keep fuel from backflowing to the tank)

2-Hook up the TCS system as it controls the spark advance. Previous owners disconnected it and is causing a variaety of problems.

3-Change the coil. It is not too expensive, mine is original, and I had experienced heat issues with coils before. the worst that could happen is that I end up with a spare.

4-Add the missing heat shield to the starter, as my car will crank slowly when very hot. It helps hold the starter on, too!

Hopefully we can find a cure for this.