Hot 318

Sure, it would be upgraded like;

New rad, for the car. If there was a 340 option, research the size. A 3 core will help. If not a new one, boil it out and make sure it can flow alot of water well.
Dump the flex fan for a Mopar Viscous fan. Seriously, much better.
A MoPar water pump. The HP pumps are A/C pumps. I have found the MP
prices cheaper myself over a regular order of the same part.

After this, re-check your timing. To much can cause un-do heat and boil stones.

I have found good results from water wetter.
Sounds like the flex fan has got to go. I have a steel 4 blade (original) and a new steel 6 blade. Any thoughts on the best?