When I first rebuilt my 235 it was running hot. It ran okay, but was hot and started to boil the fuel. The main bearings weren't getting enough oil and it developed a knock. I had issues with the engine where it would run great at high idle in the garage for hours without getting hot, then when you took it out for a drive it would seize the rear main.

I'm not saying that's your issue, just sharing my experiences as to possible reasons for your hot running issue.

1946 GMC Pickup - S-10 Frame, 455 Buick, TH400, original patina.

My 46 GMC on Photobucket