Modern 318 in a 72 duster.. Possible???
It can be done for sure...seen a 73 Dart with 318 magnum swap at the track running 13.2's all day long. The only mods were the Mopar Performance cam for a Magnum ( there is only one available from Mopar for the Magnum). Very mild sounding cam. There are plenty of choices available out there in the aftermarket though. If you want to get real aggressive with the 318 magnum, I would suggest a 210X from KRC Performance.
And don't listen to the "opt for a 360 instead"...My stock 318 5 speed Dakota beat up PLENTY of stock Dakota R/T's. It responded MUCH better with equal Mod for Mod to boot. The 360 has ALWAYS been a "truck motor". The 318 is the sister motor to a 340. Cubic Inches will not necessarily win a race. If this was true a 440 would stomp all over a 426 hemi. I also will say to the naysayers I have a 2.4L SRT-4 that stomped all over a built 454 El Camino.