426 Hemi or 5.7 Hemi for Duster

You want to drive it, or look at it?

How many different models were available in 69 vs today? Knocking the Gen III Hemi because they're plentiful is pointless. They're plentiful because they're worth it. I have a 2012 Ram and a 2004 Grand Caravan. They get within 1mpg of each other, but if I need to pull out and pass in the van I pray first. Not so with the Ram!

The 426 is awesome, no doubt about it. Not the easiest fit in an A-body, but the Gen III has its challenges there as well. For a 450-ish hp build on either, the Gen III offers a better balanced package, with better economy and driveability, and you should be able to do it cheaper.