[Flying Toaster]

I will forget the prop valve idea.
The issue occurs whether I use my street tires 205/50 & 225/50 or the autox tires, 225/45 & 275/35.
I'm sure one contributing factor is weight loss in the front when I went to RS FG front bumper and FG front fenders.
Of course I just had the alignment done last year once I thought I was done with suspension mods (ie bushings, bearings, T-bars). I don't have the alignment specs off the top of my head, but I recall maxed out caster & camber [-1.5/-2.5], toe'd out & in, etc..
FWIW, my T-bars are 21/30's. Shocks are Boge's.
I will get the brakes back together and re-evaluate. Perhaps it was just a caliper hanging up all along.... fingers crossed.