1967 326 engine 2 speed powerglide. When I drive the car for a while and it heats up, when I shut the engine off and try to re- start it will turn over very slowly like if the battery was low on charge. It only happens on hot days and when the car has warmed up. If I let it sit for a few minutes it will turn over strong again . I’ve replaced many parts trying to correct this issue. New battery , starter , new heavy duty 1.0 battery cables , Ford Solenoid Kit with heavy duty wires, more shims in starter, new coil, removed and cleaned all body ground wires , and new thermostat for heating . None of this has corrected the issue. I’ve seen many post on here having this issue, but unsure if anyone been able to find the fix. Any advise would be greatly appreciated.. Thank you all