Oh man, my brother has a 9" in his 68 camaro so i can ask him. I know it was shimmed up and he took it out and lost the shims and when it came time to put it back together he had to send it out to a chassis shop to gte the car to launch again, however he was drag racing the car strictly, im not sure if you would have to go through that if its a street car.
your situation is slightly different there may be some better links than this if you look
http://www.bankspower.com/camaro-RigidRear.cfm
Other wise find a local chassis shop, Ed Quay may still be in NJ, im not sure where you would go in CA