Can I use wheel spacers?
 

I have 15x8 Draglites with 255/60/15 tires and they are still rubbing the quad shocks. I tried flipping them around backward, but it rubs when I corner. Can I use a spacer with these wheels/lugs. I am concerned about the amount of thread in contact using the SST open end lug nuts.

You could always remove the quads. Your rear end will make a bit of a clunking noise when you take off, but it's better than having your wheels fall off, which I have seen happen with the use of spacers. I've heard quite a few people advise against them as well, but I'm no expert on them to say why, or if it is fact that they cause this to happen.

You could always go with a torque arm/panhard bar setup too. That will negate the need for quads and the upper control arms as well.

Clunking
 

I have already heard the clunking with the quads off... What is it?

the clunking is the axle moving back and forth, my buddy has wheel spacers that he picked up at Napa to install 93 cobra wheels on his 93 gt, they work good with no problem, they are the type that bolt on to the studs you have, you mount the wheel
onto the new studs on the spacer, they are not cheap, think his are 1.5 inch, and cost close to 200.00 for all 4......

SNKMUG
 

SNKMUG :

Can you get more detailed information about the wheel spacers that your buddy has?? I am currently trying to fit 93 Cobra wheels on my 89 GT and am having problems with the tires hitting the quad shocks.