So by the time you buy the MW main caps and have them machined to fit, you could have bought a junkyard Dana 60 and had it narrowed to fit your car. The gear, spool, and axles cost the same for both rears.
I just don't see the point.

CHIP
'70 hemicuda, 575" Hemi, 727, Dana 60
'69 road runner, 440-6, 18 spline 4 speed, Dana 60
'71 Demon, 340, low gear 904, 8.75
'73 Chrysler New Yorker, 440, 727, 8.75
'90 Chevy 454SS Silverado, 476" BBC, TH400, 14 bolt
'06 GMC 2500HD LBZ Duramax