SCCA® Solo classing — unofficial guide
What autocross class is a Ford Mustang GT (S550)?
FSStreetBSTStreet TouringESPStreet Prepared
A stock 2015–2023 Ford Mustang GT (S550) runs in FS (Street) under the 2026 SCCA Solo Rules. Built to Street Touring allowances (within BST tire and wheel limits), it runs BST.
Class by preparation level
| Stock (Street) | FS |
| Street Touring | BST |
| Street Prepared | ESP |
| Street Modified | SM |
| Prepared | — |
A “—” means the car isn’t listed at that level; a build lands in the least-prepared category its modifications allow.
Also eligible for
CAM-CClassic American Muscle
From the 2026 rulebook (Appendix A)
Street: 'Mustang GT (incl. Performance Package Level 1 & 2) (2010-26)' = FS. ST: 'Mustang GT (excl. Shelby & Boss 302) (2005-23)' = BST. SP: 'Mustang (non-GT350, non-GT500) (2015-23)' = ESP.
Other FS cars
Unofficial guidance verified against the 2026 SCCA® Solo® Rules — always confirm against the current rulebook before competing. Classing data cites the exact Appendix A wording it relies on. Spot an error? Report it on GitHub.