Thomas, Unfortunately you have a common problem for early Camaros (I have the same problem, but on 1/2 in).
There are a LOT of past posts on this subject, so please do some searches.
In a nutshell, the possible causes in no particular order are:
mismatched front or rear springs
binding or worn bushings
front spring not seated properly
twisted subframe or body (not common, mainly accidents)
body to subframe bushings not the same thickness (may be due to rusted perches or worn out)
bent front suspension
As with mine, the problem might be the passenger front (if raised would cause the rear to go down)
Do a measurement on all the critical locations on the body and frame. Then jack up the rear with the pointy end of a piece of angle iron in the center of rear pumpkin, then measure front. The do the same to the front and measure the rear. Hopefully you can track down the reason.
[This message has been edited by KevinW (edited 10-17-2001).]