Mario I'm curious about the 1/8" pull that you are compensating for when welding on the back brace. What kind of brace are you using, and have you seen this warpage consistently?
That seems like a lot of pull to me. FWIW I use the Competition Engineering back braces and weld 3/4" beads with a fan blowing on the housing, allowing everything to cool before welding another small bead on the opposite side, etc. It's fairly time consuming but I'm not seeing any warpage of the housing after the brace is welded on.
I usually buy a Currie housing with the axle tubes welded in, and then weld on the ends myself because I like to use Mark Williams ends for their oversize pro-street bearings. I have a jig setup that I built just like yours, with donuts for the case and also for the ends, to get them welded on straight. I use this setup to continuously check the housing straightness as I weld on the back brace, four link brackets, shock mounts, etc.
I like my method but it does take a while to get the rear end welded up, and I'll admit to the desire of welding a long, solid bead while I'm working on an axle housing. Its interesting to see how you are approaching the warpage issue.
1969 R Code Mach 1, Drag Week 2005 Winner BB/NA with 511" FE(10.60s @ 129), Drag Week 2007 Runner Up BB/PA with 490" Supercharged FE (9.35 @ 151)
1964 Ford Galaxie, Drag Week 2009 Winner Modified NA with 585" SOHC (9.50s @ 143)
1968 Shelby GT 500 Convertible, 492" 667 HP FE
2005 Ford GT, 2006 Drag Week Winner, 12.0 Daily Driver
1969 Ford Galaxie XL, 460 (Ho Hum....)