I bought these drop springs off Ebay for my '99 Z28 (the guy I bought them from said they were 4th gen springs). They definitely aren't 4th gen springs. The rears are identical to my 3rd gen springs (but about 1" shorter). I can't compare the fronts (my stock ones are still installed in my '82). Can any of you that have 3rd gen springs laying around take a look at let me know if you think these are for a 3rd gen. The fronts are about 14" in height and 4.75 in diameter. I'm not sure if I want to sell them or use them, but really want to know what they are. They say Ground Pounder on them, but I can only find reference to Mustang Coil-Overs when I Google that.

The front is on the left.

Thanks,
Tom

 

3rd & 4th gen rear springs are interchangeable... fronts are not.

 

That could be why the previous owner thought they were for a 4th gen. When I went to install them on the '99, I never got to the rears. Once I discovered the fronts were completely different, I stopped.