# Suspension Alignment Specs



## Leval (Dec 11, 2007)

In considering the tall spindle disc brake upgrade for a 67 GTO I've noted that the "after conversion" caster spec is typically 3-4 degrees positive while the OE spec is 1 1/2 degrees negative. This change is of course accomplished by the new upper A-arm but I would like to know the reason that the GM A Body had negative caster in the first place. By 1974 the G Body was spec'd at 3 degrees positve while the A Body continued at minus 1 for manual steering and 0 for power steering. In 67 it seems all other GM models used positive camber. Anyone know why the A-Body was different?


----------



## The_Humbler (Nov 18, 2007)

Because of the poor suspension geometry...... Which the B body spindle only makes worse... 

Do some research on the Pro Touring type forums before you waste your money!


----------



## 05GTO (Oct 6, 2004)

Leval said:


> In considering the tall spindle disc brake upgrade for a 67 GTO I've noted that the "after conversion" caster spec is typically 3-4 degrees positive while the OE spec is 1 1/2 degrees negative. This change is of course accomplished by the new upper A-arm but I would like to know the reason that the GM A Body had negative caster in the first place. By 1974 the G Body was spec'd at 3 degrees positve while the A Body continued at minus 1 for manual steering and 0 for power steering. In 67 it seems all other GM models used positive camber. Anyone know why the A-Body was different?


Probably because the A-body offered a much lighter inline 6 and with the extra weight of the V-8 the steering axis inclination was changed thus requiring the negative 1 1/2 degree caster. Also, the Tempest 233 and 235 series had a 54.4" ride height compared to the 237, 239 and 242 ride height of 54.9".


----------



## Leval (Dec 11, 2007)

Thanks to both The Humbler and 05GTO for the responses. I'll look into the pro touring though I would guess unless there is cutting and welding of mounting points the only other bolt on change would be a longer lower A-Arm and from my current layouts that doesn't seem to be a limiting factor. Spring and damper rates can be be changed with any geometry. Maybe the pro touring sources can shed some light. Looking at the SAI the A-body was 8 1/4, the Corvette was 7, the Camaro was 8 3/4, and the B-body was 7 1/2. The A-body went to 9 in '68 and 10 1/2 by '74. Seems the SAI was independent of engine or ride height.


----------

