I think Mike has it right. A stock or near stock engine has much less cooling needs than a BIG mill.
A lot of problems with heat have to do with proper internal bearing and piston clearances, oil pump, and proper oil cooling. And don't forget which shroud/fan speed setup you have. Jetting and valve adjustment play a factor also. And don't forget proper ignition timing. Even which head casting matters, plus all the proper tins.
It all matters.