Fan options 318 Barracuda

that radiator is certainly not stock. it *appears* to be a slant six radiator from a later 70+ model of a-body

the only thing i hate more than overheating cars is chasing down an overheating problem.

i'd go spend big dumb money and do something like this:
https://www.manciniracing.com/3rowrera22wi1.htmlhttps://www.manciniracing.com/mrebofansh.html
then add a clutch to the fan you've got and you should be in business.
(pending waterpump, appropriately sized pulleys and t-stat)