[techteacher5561]

Rick,
same thing happens w/ my 68 vert. ( mines not a GTO but the Lemans is very similar) I noticed that there is supposed to be a rear spring insulator between the spring and frame/body. Mine are looking pretty sad, may not even be the right ones. I'm swapping springs before the spring as my car has a little lean, whihc I'm thinking is a soft spring on the drivers side ( no I'm not THAT fat to make the car lean-LOL) When jacking up the rear of the car with my jack under the rear diff one side compresses first- this is why I'm thinking soft spring on that side. Who knows how old these springs are.

I'm watching this thread to see what other comments or solutions might be.

oh yeah, if you drop the car w/o centering the spring eventually you get a hell of a bang when it re-seats itself huh?

What kind of shocks are you running? I've got some goofy support coil bolted to the shock- car came this way when I bought it. Not sure if this was a normal pontiac thing or if the prior owner wanted extra lift w/o air shocks.

But I read a thread somewhere where these "booster coils" will contribute to wheel hop when you drop the hammer down. I've got wheel hop when I dumpt he clutch So I'm probably going to try to remove them and do a little testing.

Howard