Requesting cooling/radiator/fan help for a slant six

Dan, If you ever lived in some good cold temps in IN in the winter, you would indeed have seen that the engines needed cardboard to get any sort of heat in them. Well maintained, coolant up to snuff, t'stat just fine. I thought you were in CO for a while....

As for engine surface being large, well it just IS LOL. You are welcomed to measure and let us know, but it is pretty obvious. Heat output direct from the engine block and heads just is.... So maybe it is not a LOT more heat...I have never had any heating issues from a stock /6. And my family and inlaws had 6 of them from 68-76, all A's.