Thank you all for the numerous tips and tech related facts for: thermal clutches, high flow thermostats and the Chinese sending units which do not relate well with our gauges.
The 2705 thermal unit arrived overnight, and it was the perfect fit, almost a belt gap between the fins!
The high flow thermostat is a positive addition for the cooling system.
I did find a Stewart Warner sending unit in the other 413. When cleaned up you can see the SW in script on the flat side of a hex. So I put the Chinese unit, no ID on it, into the spare motor.
Difference in operating temp when idling in ventilated garage for 40 minutes and rpm's raised to 2k for intervals of 5 minutes: 184 at gooseneck with digital meter, and low side of temp. gauge !
Now I will need quotes and a good body shop for total bare metal and one color paint application (LOL).
And a very special thanks to Mr. 300 K, who was highly instrumental ( IOU) in having
both motor mount reborn in the flames of the Phoenix.
The resources amongst this special group are phenomenal!
Happy 4th to all, see ya' in PA!
Dave and the K