3.0 engine swap
I have done plenty of engine swaps, I just don't see why you would want that V6 harbor bomber POS crammed into an early A engine bay.
If you want "smaller & still powerful" use a heavily boosted 2.3L ford. Take several hundred pounds off the front end, and give yourself room to work.
If the A body I was looking for had been equipped with a tired /6 I probably would have done a swap of some sort too... but the last guy spent the money & time to put a decent +.060 318 & a 727 in the car already. Always fun to tell the Mopar guys I have a "327"...
FYI, "Valliant" + "Plymouth" - (a few letters) = VOMIT. Which would be appropriate for any mister-bitchy transplant.
B.