Depending on the year and application of that B body 8 3/4, you may not have to shorten. Currently I have an 80 volare and measured a bunch of stuff and ordered a new S60 from Strange. I believe I used tech archive data to find that 1" less width from a 69 road runner dana would work, so they verified with me that the standard pinion offset would be retained and whipped one up. 1" total reduction in length(1/2 " per side), and I've got 275/50r15 drag radials on it, on 15x8 magnums. Note: the springs are moved in about 3/4 per side on mine so Strange sent pads seperate, so I could figure pinion angle and custom locate them. It works great!