Does anybody know the diameter of the Formula S torsion bar?

The F/S had 0.870" T-bars in '66, I assume it was the same in '65.

In '65 the standard suspension had .85 for the 8cyl. .83 for the 6 cyl. and as he said .87 for the H.D.suspension on the F/S

I picked up this chart somewhere, showing the different A-body torsion bars.

Chassis: A-Body (35.8" torsion bar length)
Diam------Orig P/N----ID# MP PN MP ID# RATE-----------APPLICATION
0.81------P5249148----446,7 82--------------------------------Drag
0.83------2535888,----9 888,9 92 ------------------------------6-cyl
0.85------2535890,----1 890,1 101 -----------------------------318
0.87------2535892,----3 892,3 P5249149 892,3 109 -----------340
0.89------2535894,----5 894,5 P5249150 894,5 120 -----------383/440
0.92------P5249151----448,9 137 ------------------------------XHD/Solo
0.94------2948634,----5 634,5 149 76 --------------------------Police
0.99------P5249151----450,1 184 -------------------------------Solo,perf
1.04------P5249153----452 224 ---------------------------------HD solo,roadrace
1.09------P5249155----453 270 ---------------------------------Circle Track
1.14------P5249155----454 323 ---------------------------------Circle Track

Click here for another Torsion Bar size chart