Tony, the Factory Five Racing Forum has various suppliers of wheels and tires for your buying enjoyment.
http://www.ffcobra.com/cgi-bin/ultimatebb.cgi
Depends if you want the original style or going with something different. I know some that are going with Cobra ( mustang ) wheel setup. Also, with the 15" wheels high performance tires are almost non-existant. The BF Goodrich are mostly SR speed rated, there are several other manuf. that have produced others such as Pirelli and Michelin but you are limited to sizing. With 17" wheels you can pretty much get what you want.
Hope this helps, Randy
P.S. my wheels are PS Engineering Halibrand replicas ( 15" period correct ).