|SFM6S2279 1966 Shelby Mustang GT350|
I don't think a lot of "race car" modifications were made at all on the car other than the cool side exhaust and the R Model roll bar. It was certainly nothing like the vintage race cars of today or even of several years ago. In fact, if I recall, he drove the it to Road Atlanta, raced in the Walter Mitty Challenge, finished in 3rd place, and drove it home!!
It is difficult for me to believe this photo is 30 years old now!!