Paul;

 
 
The EGT depends on  your operating conditions, of course; but are not too high.  I found on  the dyno that at max power mixture (rich of peak) and WOT at 5300 the temps  were right about 1550F.

 
 
I also found that  the coolant flow rate is 35-40% higher without a thermostat than with.   So it is no surprise that your running cooler.

 
 
Al

 

Paul, I also noticed your coolant hoses are about 1”. Going to larger ID may increase the flow and improve the cooling. Mine are 1.5” ID aluminum tubing.
Buly