I had a 55 Dodge Royal Lancer with the little hemi- - - -nice engine! It will be a novelty, for sure, but I think I'd choose a different transmission if possible. The Powerflite shared a common problem with the Chevy Powerglide- - - -two speeds, too low and too high! If you can adapt the small Torqueflite (901?) to the hemi, you'll have 3 speeds and a lot more rugged transmission to boot. I don't think the Powerflite shift quadrant had a Park position, just a transmission mounted drum-type parking brake, IIRC.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!