Well I flipped it and reinstalled it with the smooth, concave side to rear. Took the same route, corners, relative speeds and stops - and it didn’t exceed 200° or blow off.
While sitting stopped there is also significantly more airflow out the side louvers as well. (It does have engine pans)
So, (with out rehashing the 2,4,6 blade benefits -
http://www.tulsamodelafordclub.com/m...-fan-air-flow/ ), it does appear it was installed backwards, and the smooth, concave side does go towards the engine.
The radiator and engine are virtually new from a professional engine rebuilder, and still flush cleanly.
This may not be the entire issue, but at least it is a significant improvement, and it doesn’t appear it will be dumping coolant on every run. Will see ....
Thanks for your input and verification. It just didn’t look right.