I'm not disagreeing with you. That being said, I can recall at least 2 times when I was able to run the heater and not over heat my car--possibly saving the engine (not talking about the miata here)

I had to do it a couple of times while autocrossing the miata before the turbo. Issue with the coolant mix, once I sorted that out I had no problems. Now with the bigger rad I have no issue with heat at all.

In Russia it was common to run the heater on Volgas to prevent them from over heating in the summer.

sounds fun!

I have the heater on full blast at the track, set on defroster to stay away from my feet, cause the exhaust makes that area tosty enough as is. works great, I go a lap or two more with the needle at 11 o'clock before it rises to 12 o'clock and I back off for a lap or two.

no worries though, I have the godspeed radiator on order.