The high torque starter makes no difference with heat, only with compression and timing. The solenoid is in a poor location and seems to degrade from extended exposure to heat. It's not a problem if you don't do frequent short trips.
The "mini" starters don't seem to have the heat issue, and can be removed with headers and long branch manifolds. They just don't look stock, and are a lot more expensive.
Vikki 1969 Goldenrod Yellow / black 400 convertible numbers matching