some info on a 440

Lets not be so fast to assume there's not enough radiator...I know it's a different year model, but my Dad's Ramcharger has a 318 in it...that thing came with a 3 core radiator and plenty capacity to cool a big block...but if it hasn't been serviced in a while or well kept, it may just not be flowing well enough. With the electric fan, it may not be pulling enough air through the fins. T-stat...unless it's not opening all the way or a really hot one, less likely. Carb...I can't say I follow your logic here unless it's running slobbering rich and very retarded timing-which could also be at fault.

We really need some more info from the OP...

What say ye, Sir?