‘73 Duster /6 to 318 Swap

Ah, okay. In that case, I’ll just go the 727 route! As far as the exhaust goes, I’d like to find a nice set of headers, maybe some kind of cool side-exit exhaust, I dunno.

Surely mounting an aftermarket aluminum rad wouldn’t be too hard?
I've ran, and I'm currently running Champion aluminum radiators. Cheap, Chinese from ebay usually 180 bucks to the door. Fit good, maybe just oval a hole or two. Never had them leak, and they cool well. As far as headers, there is a big price range. Ebay/Summit is full of cheapies, and then you can spend more towards Dougs/TTI's. Bare, painted black, or ceramic coated will also influence the price. I personally like Dougs for fitment.