My First MOPAR Build!!!!
No K frame swap needed. Schumacher creative services ((engine-swaps.com) for swap engine mounts. I have used them 3 times with excellent results.
A 360 is cheaper, more readily available. It will make more torque and peak very similar HP numbers a few hundred rpm earlier than a 340, which holds onto its peak rpm HO level longer because it is a short stroke engine.
The wiring needs to be shortened or lengthened. Snip and adjust as needed to fit.
An 8-1/4 is 75% cheaper than a 8-3/4 of which the 3/4 will hold 30%+ more power.
There are many upgrades for brakes.
6X9 speakers in the rear deck.