Talked to Powermaster. A human picked up the phone and with 1 transfer I was talking to a tech support guy. That was nice. The started they recommended is the 9513 which is clockable and higher than standard torque. He said their experience with heat soak issues (with their starters) has been that it's always a low voltage situation and not a starter problem. Sort of what you would expect a starter manufacturer to say I guess. Nonetheless, I will check wire sizes and verify that there are no corrosion issues or grounding problems. He also said an insulation blanket on the starter would void the warranty. Again, what you would expect them to say.
For this motor/trans combo which is 360/904, TTI lists 2 Chrysler part numbers and 3 mopar performance part numbers. The RobbMc starter will not work.