Starting Troubleshoot - Heatsoak?

[Jferrante]

Hey everyone - need some insights. My 64 is having starting issues after the initial startup- for example I am starting the car in the garage let it run and then it has trouble firing up again after getting hot. I just installed the heat insulator for the starter and also wrapped the headers with insulation wrap - same problem. Car barely turns over. Let her sit for 5 mins and fires up, turn it immediately off and try again but trouble starting.

As a reference, the car is freshly rewired, new battery, leads and new ground.
If this was a heat soak issue shouldn't I be good after the double insulation?
Before buying a new starter I want to confirm here.
Thanks