I think it would be cool to leave the 6 cyl in it. It would be different and it would probably be more rare than a 340 Duster. Check out www.pantherpink.com there is a lot of information, including several Dusters! :thumbup:
I agree on this, but boy would that be difficult. I think I would pull the original drive train and clean it up and properly get it ready for storing and then "bag" it. Then either put that 340 in it if you can find it and afford it, other wise BB that baby. I looked for quite a few years for the right 71 model, I really wanted (in this order) either a Demon, Duster, or a Dart, well the combination of $$$ and finding resulted in the recent purchase of the Dart, and I'm more than happy !. However if I had got either the Demon or the Duster it would have been done in FM3, the Dart although not original in black will stay black.