I mounted mine in the "stock" location in front-of the spindle on my '68 A-body, and in back of the spindle on my '70 e-body (see pic) The brake lines and calipers you need to use differ depending if you put them in the front or rear of the spindles.

This link has some good info. You can also look up "Doctor Diff" on this site if you have further questions. He is a great resource and a good man.

http://www.moparaction.com/tech/archive/disc-main.html

1970 Plymouth 'Cuda #'s 440-6(block in storage)currently 493" 6 pack, Shaker, 5 speed Passon, 4.10's
1968 Plymouth Barracuda Convertible 408 Magnum EFI with 4 speed automatic overdrive, 3800 stall lock-up converter and 4.30's (closest thing to an automatic 5 speed going)