45rfe over nag1

You'll have to do floor pan and torsion bar crossmember surgery to use either transmission, but I know that wasn't your question. I would choose the 545RFE over the Nag1. Now that the8HP70 is in play, I would pick that over either of the others. Back when I was planning to do a 5.7 in my 70 Duster, I bought a 545RFE that had been in a 2007 Chrysler Aspen that was crashed with 37K miles. I made it fit the car with the Hemi. Hotwire Auto could make a harness to operate the hemi and also the 545 by using a PCM from a 2005 Dodge 1500. I chose the 545 because it is a very durable transmission (electronics aside) AND, it has a slip yoke tailshaft. With a Nag1, you gotta do all that driveshaft cobbling to get it to work with an add on controller. I lost interest in the Gen 3 swap and sold all the stuff to another guy who put it all in a 70 Dart and got it going. I don't think the PCM from the Charger will run the 545, so talk to Chris at Hotwire Auto if you want the simple fix. Good luck with it!