check the springs on the rearend, it doesn't sound like the shock would be causing that to me. you can actually take the shock completely off and it won't be that loose. If I were you I would look to make sure there is actually a spring on it, then check and make sure it's not messed up. secondly I would look at the shock mount area and make sure there's no cracks or anything like that in the area. maybe a loose/missing nut somewhere. If I had to bet, I would bet on the spring being gone or broken. sounds goofy but I've known people who had similar problems and go check and there actually missing a spring, I swear those things fall off somehow
. Secondly, the main reason the mustang/camero's have always had a solid rear axle is that the majority of people who own them use them for 1/4 mile drag monsters, they market the stang and chevy the camero towards the 1/4 mile crowd as a cheap car that you can turn into a beast for very little $$. If they were to switch to an independant rear end then most of the parts would cost 5 times the ammount. generally speaking a mustang, especially an early 90's late 80's mustang is a great buy if you are looking for a 1/4 miler that you can buy reasonbly cheap and turn into a beast for a few grand more. Just take a 92 mustang and throw a crated up V8 in it and a shiftkit and your set. anyway good luck on the stang, let us know if find the culprit. If your still having problems figuring it out, run it down to your local garage and have one of the people out back working come take a quick look at it in the parking lot, most of the time they'll figure out whats wrong and won't even charge you sense its not in there garage but in the parking lot. I have a 68 camero and anytime I need to get under my car to work on something or to inspect something I just run down the street to discount tire and have throw it up on one of there lifts, I started building that car about 5 years ago, so needless to say I'm on a first name basis with most the people there