thank you mr. P.
i have narrowed several rears over the years, using an 1 3/4" or 2" bar, plus machined pucks for the ends and differential case.
some for leafs, some coil springs, and some coil overs.
these were followed by straightening the housings using a 12" piece of very heavy I beam to clamp the housing to, [it's what i had laying around] plus heat and a jack or press as needed. also to make sure the bearing ends were parallel with each other in both the vertical and horizontal planes, approximately 18-20" out from center line.
i just never back braced a housing before.

thanks again mr. P.