Had a similar problem, just used a torch and cut them off ,ordered new bolts and chrome shock towers from Luttys and spot welded the bolts in place with a wire feed when I reinstalled them. This is a common problem with the early Novas. Did you get the CPP kit with the upper A-arms or just the lowers? From what information I've been able to gather it would be a good move to replace the ball joints in the kit with some good quality units, ie: Moog, Napa etc.
