[marcocsx3121]

Not definitive, but when I bought CSX 3121 in November 1969, it wore the FIA Halibrands front and rear (6-1/2", 8-1/2"). I eventually traded all four for a pair of 9-1/2" Halibrands, having already scrounged up the matching 7-1/2" wheels for the front of my Cobra. The FIA wheels ended up on the Hoppe/Motion drag 427, which, interestingly, just won a blue ribbon at the Amelia Island concours. In the photo of that event, my wheels were still on the car.