Thanks to all for the feedback. I’d like to avoid cutting on the car or going away from the push button trans but it sounds as though that may not be possible if I opt for a crate engine. The mechanic who worked on my car last fall doesn’t like to fabricate or make major modifications so I may have to find another shop.
99.99% chance you'll have to fab a trans cross member, 100% you'll have to fab a trans mount. either of which i'd classify as "basic hot rod fab" so if you have a vice, torch, BFH and a buzzbox it's doable.
with the mopar variants: 500/518, 42/46RH the likelihood is that you could grab the mount from the donor and adapt that to a custom x-member or maybe grab the whole encharito off the chassis and then stab that onto the plaza. the determining factor on the cutting would be if there's room under the tunnel, the plaza being frame on makes the rest of it a breeze.
adapting the pushbuttons presents a unique challenge. i know that there's a kit that allows early 60's pushbuttons to utilize later transmissions, so i'm sure with some fettling that could be made to work. however, you'd likely want somebody that's familar with the system and torqueflite transmissions to perform that kind of work. the other option is an aftermarket floor shifter, which is kind of dealer's choice in the broadest of terms and requires a small hole in the foorboard so that convenience comes at a cost.
then you just have the consideration of how to control the OD and lock up on the trans. easy-peasy.
