To clarify my situation, I am using year one magnum wheels. They look identical to the American racing ar500s but there may be some differences. I found that by taking the stock center caps for the Buick wheels and bending the tabs outward slightly they will fit in with a positive detent. I don't trust it enough to not use some sort of adhesive or retainer but it will work in my situation
Thank you for the reply. I will buy just one to see how it fits. If I can make it work I will buy the other 3.
Update: I ordered one 1973-1978 center cap from Mitch Romanowski for my 1965 Skylark to see if I could make it fit on my 17" American Racing VN500 wheels. I had to bend the tabs in very slightly but it fits just fine and fits nice and tight. This cap is 2 7/8" in outside diameter and fits the 2 1/8" hole. I am quite pleased with how it looks. I will order 3 more. Here are two pictures that show the difference. Thanks to this thread for setting me in the right direction.
Managed to get mine to fit and click into place just like the stock wheels. I added a washer on bottom of the retainer for each screw to space the retainer out and grab the lip of the wheel better. I will probably still use a little bit of glue around the perimeter to make sure it doesn't come off too easy. Again since my wheels are year one wheels and not american racing I think hub is different.
