IMHO.just send the housing to Moser and have them cut it to A-body specs and weld the new perches on with 43" centers..shiping x 2 and about $65+ to narrow it

set of the $299 custom alloy axles with greens and large brake off set..

you can run any brakes from an 8 1/4, 8 3/4, 9 1/4,D-60...B,C,D,E,F,M,R body axles

unless you rather do the funky offset on rims

I did this for my 68 Dart and then swaped it into my 85 truck

still less $ in it than buying a 8 3/4 thats does not bolt and play and fit correctly
just a suggestion