Denso Starter Heat Soak?

Definitely having problems with my denso starter. Been having issues with my 75 318 running hot lately (I don't even have headers yet). After driving it for a while, I'll shut the car off and the starter bricks. I've got to wait for it to cool before I can start it again. I just bought some heat wrap from summit; fairly cheap. Going to try and see if that helps until I can figure out my engine cooling issue...