318 build #2 "cost minded" for the '74 Duster

Yup those would work as well. I was trying to keep my recommendation within the bucks down approach as @318willrun said from the start. Guess it comes down to what heads do you have on hand, and how much work are you able to do yourself to them to keep costs down.
WWAJD (what would average joe do?)
Yep, probably best with Magnum heads. No issues with valve train and they are good heads unless they are cracked. That doesn't seem to be a huge issue either.