OK thanks guys for the many responses , it looks like I'll be looking for a set of .860 torsion bars for my B-body. This was a very informative post !

E. Williams 65 Coronet 500 3400lbs w/d, 446, Indy EZ'S, A&A transbrake,Comp 650 lift cam, 6.50 @ 105 mph 1/8th 10.25 @ 130mph 1/4