Stock Category


As with most motorsports organizations, what FAST calls “stock” isn’t really stock. We allow a certain set of basic modifications. But, since we had to call our “least modified” set of classes something, we chose to call them “stock.” If you autocross with other clubs, be aware that FAST stock bears no resemblance to ANY other club’s “stock!”

Is your car stock?

If your car is a US-market mass-produced vehicle, it is eligible for stock if it has NONE of the following modifications. Any and all modifications not listed below are allowed in the stock classes. (don’t go overboard and make us change that!)

  • Internal engine modification (crank, cams, rods, pistons)
  • External engine modification that alters fuel delivery (alternate carb, altered fuel injection, fuel-air ratio adjusters)
  • Modification to engine control electronics (including code changes, reflashes, replacement ECUs, piggyback ECU’s or other devices that alter or inhibit signals from or to the engine or the ECU) that are capable of increasing fuel mixture or raising the level of boost.
  • Addition of non-factory forced induction or modifications/upgrades to a factory forced induction system.
  • Non-factory engine replacement
  • Welded chassis reinforcement, including welded roll bars/cages
  • Alternate or altered springs
  • Modification which places alignment, suspension geometry or ride height parameters beyond factory tolerances. (Regardless of factory tolerances, camber up to -2.0 degrees is permitted and camber in excess of -2.0 degrees is prohibited. Crude on-site camber measurement, if requested, will be +/- 0.2 degrees.)
  • Alternate main body panels (doors, hood, trunk lid, fenders, roof panel, windows)
  • Removal of significant factory interior parts (seats, interior panels)
  • Replacement of driver or passenger seats with non-reclining race seats.
  • NOTE: A Stock class car may be upgraded with factory optional parts (such as original equipment performance package springs) and stay in a Stock class only if those parts are available as an option on the same model and year of car and that car is classified in the same class.

Street Tires?

Made it past all the “stock” qualifiers? Good, now let’s look at your tires. This is simple. If they are DOT approved and their treadwear rating is 140 or greater (check the sidewalls), we consider them street tires. (NOTE: A handful of cars come from the factory with tires that do not meet this qualification. It’s a big deal to us! If your tires have less than 140 treadwear, sorry, you can’t compete in a street tire class.)

Identifying Your Class

If you’re on street tires, all you have to do now is find your car on the Stock Class car list. As many other clubs do, we share the SCCA Solo car classification lists because they are thorough and regularly updated with new cars.

Stock Class Car List (pdf)

Use your SCCA “Street” class to choose your FAST “Stock” class.

  • S0 – Stock Street Tire 0 (SS)
  • S1 – Stock Street Tire 1 (AS/BS)
  • S2 – Stock Street Tire 2 (CS/DS)
  • S3 – Stock Street Tire 3 (FS/GS)
  • S4 – Stock Street Tire 4 (ES/HS)
  • S5Voluntary bump down for ES/GS/HS cars (must meet requirements)

S5 Class Rules

ES/GS/HS cars may “bump down” to S5 if they have a tire size no wider than 195, and have no limited slip differential other than a factory Viscous type.

NOTE: If your car is listed as “excluded” in the SCCA list, but is not an obviously unstable and top-heavy vehicle such as an SUV, off-road pickup, or minivan, contact us. We may allow it. (for example, vehicles like the Fiat 500 and Ford Fiesta we will allow to compete in stock form as long as the tires are close to factory-equivalent… but, if you’ve improved the tires without improving the suspension, we would have to disallow it)

Last update 9/2016