Old Question from and Old Mopar Guy

Yup, sounds like you are on the right path. Motor mounts, I think the tranny mounts will work, you will need a trans from a V8 (904 or 727), driveshaft will need to be changed or a good shop can adjust the length for you or make a new one. Radiator upgrade is a must.

8 3/4 rear end from an a-body is the best choice but they are hard to find and expensive. You could use an 8 1/4 f-body (Volare/Aspen) rear or get a 8 3/4 from another car, then have the ends cut down to the right width for your car, you can then buy axles for an abody or get new ones with the 5 on 4 1/2 bolt pattern.

Best front brake upgrade is get a set of disc brakes from a 73-76 a-body with discs, they will bolt in nice and you will have the better 5 on 4 1/2 bolt pattern, this is plenty to stop your car. (Upper control arms, spindles, calipers, lower arms) Also, rear brakes from the above mention axles will work fine.

You may want to get a set of V8 or heavy duty torsion bars, it will handle way better than the slant six ones. You may find that some shifter linkages are different as well but that stuff is easy to find.

Don't forget fatter rear tires for that 360! Good luck!