you know the power booster may be a problem--mine are all manual and they stop really well--I know my 66 originally had added on power drums--very touchy I think the pedal pivot point for the brake rod was different with power brakes--less of a lever arm with power and more with manual--the power brakes did well you just had to remember it only needed a touch--if you stomped on the brake you would go thru the windshield---i think some after market boosters are smaller in diameter to more easily fit a 62 never really measured a 62/63 booster diameter--the backing plates and drums do need to go together and should also bolt right up--i guess the wagon rears are probably bigger than the 62 original--that 66 probably has a 9 3/8 rear but are the axle housing the same size where the backing plates bolt up? they probably are but i would measure that
