I was wondering how they go on. Do they just pop on or screw on or something? Are their different sizes and if so, how do I know which size to get for my rims? Do I need any special components in the centers of my rims so the caps can go on? Please help.

86 Trans Am, 5.0 L, 4bbl, 305 ci, True Dual Exhaust

 

If you can post/attach a picture of your wheels, someone might be able to help. If you can't post a picture, you might find several sample wheels at http://www.gmtips.com/3rd-degree . Mike had a sample of all factory wheels posted there somewhere.