[PNJSNAK]

Joe: had the same problem, did all the above, bought the heat wrap, checked the ground cables, even added a second. Same size wire #2 from battery to solenoid to starter, had starter checked everything fine. Before I spent the $100 + dollars on a mini starter, I talked with a bunch of engine builders. I retarded the distributor timing a couple of degrees. NO MORE PROBLEM. Don't see any change in performance, besides I don't race the car or drag race with it. Just like to cruise and occasionally get on it for the adrenaline charge we all need and get with these cars.
Good luck.
Jim