b-body rearend in a-body

X2 on everything said above. I'm about to do it on a 73 Dart. The B body perches are 44 inches, the A body 43. That's 1/2 inch on each side. If you want to spread your springs, it will bolt in. If you want to move the perches to make it perfect, you can do that.

The 65-67 housing is slightly narrower but it's in fractions of an inch. (it's still nice to have) The perches are 44 inches from 65-70.

I once saw a TSB that said with the new disc brakes, the later A bodies had a wider track on the front than the back. The b body rear will correct that :)

On the driveshaft: If you could find one from the same body style that had your transmission and an 8 3/4 rear it would work. (for example a shaft from a stock 340 Duster with a 727 trans and an A body 8 3/4 rear would work for a Duster/Demon body style if you were running a 727 and a B body 8 3/4). The a body 8 3/4 and B body 8 3/4 are the same length with relation to the position of the rearend yoke.

Here's a good magazine article on the swap: http://www.moparmusclemagazine.com/...404_8_3_4_rear_axle_housing_swap/viewall.html