Hotchkis 1820 Rear Suspension Package, Adjustable, Single Upper, 59-64 GM B Body - Manual (Page 3)

6) With the arm(s) in place, determine if any pinion angle adjustment is necessary. For stock
vehicles no adjustment should be required. If the pinion angle needs to be adjusted
downwards, the arm length needs to be shortened. If the angle needs to be adjusted
upwards, the arm length should be extended.
You should only remove the bolt at the axle end of the arm to rotate the head once the arm is installed
in the vehicle. One full rotation of the head (360deg) is approximately equal to 1/16” (.0625”) of travel
and 1/2 degree of camber adjustment.
The stock Chevrolet upper arm center-to-center length is 13-3/4” (13.750”)
The maximum suggested center-to-center length of the Hotchkis upper arm is 14” (14.00”)
The minimum suggested center-to-center length of the Hotchkis upper arm is 13-1/2” (13.50”)
Hotchkis arms can be lengthened or shortened 4 turns or 1/4" length over stock for a total of 2 degrees
of positive pinion angle or 2 degrees negative.
IMPORTANT! There MUST be a minimum of 1/2 inch of thread engagement into the head
for maximum strength!
7) Tighten the jam nut to secure the arm at the desired length and pinion angle.
IMPORTANT! The jam nut MUST be tight before usage. Then re-torque the jam nut
after the first use.