You can almost always benefit from a .5" tall upper ball joint on the GM short long arm front suspensions. You start getting into issues with the .9" tall ball joint due to ball joint angles and binding. Most often they are added along side a set of lowering springs. The reduction in the bump travel moves the upper arm upward at ride height, increasing the angle on the ball joint. Adding another .9" of effective knuckle height moves that upper arm up further. In a lot of cases, the ball joint on factory designed arms will be near it's bind point just sitting on the ground.
As Scarebird mentioned, you should contact global west and see if they reconfigured the ball joint angles specifically for lowered cars. If that's the case, I'd do a .9" tall ball joint. If not, I'd opt for the .5" tall joint.
On the A-body you may also opt for a .5" tall lower ball joint. This will further help the camber curve. Keep in mind that by adding the lower ball joint you will lower the car half of the effective height gain...or around 1/4".
__________________
-Jason
1969 Pontiac Firebird
|