A body rear

Looking at using a 63 B body rear in my 68 dart.Had a 70 8 3/4 installed with perches moved to 43 c/c with 11 x 2 1/2 drums,(running 17 x 8 bullit rims with 5.72 b/s &245 45 17 tires) way to close to the quarter lip even after trimming the quarter.I have 1 1/2 on one side and 1 3/8 on the other to the leaf springs.Am I correct with my measurements that the 63 B body rear is 58 1/2 flange to flange vs 60 1/8 for the 70 B body rearend.Also will the Dr Diff axles with green bearings fit into the housing ends (63 used the retainer nut type axles) If my calculations are correct it should move my tires inboard 3/4 per side(towards leaf springs) Any info would be great
thnx mike