Need Help finding your class? SCCA Solo Classification Assistant
STREET has ten classes and is the lowest barrier to entry with primary allowances being shocks, one anti-roll bar, and 200tw tires. Classes include SSR, SS, AS, BS, CS, DS, ES, FS, GS, and HS.
STREET TOURING builds upon the Street category allowances. Emphasis on performance improvement through “Bolt-On” Modifications. Classes include STS, STR, STX, STU, and STH.
STREET PREPARED has six classes – ASP through FSP. More is allowed to be done to the car, but they are still basically (if barely) streetable and should be capable of being licensed for street use.
XTREME STREET (XS) is the newest category added in 2020. XS is for street legal cars with modifications that move it beyond the Street categories of the traditional autocross class, but have a finished look to the interior. Classes include XS-A and XS-B.
STREET MODIFIED aimed primarily at the new wave of modified imports that are becoming very popular. Engine swaps are allowed as long as the engine comes from the same manufacturer (a 6-cylinder Honda in a Civic, for example). There is SSM, SM, and SMF (“Super,” Basic and FWD) for different groups of cars.
PREPARED has been around as long as Stock, since the Solo program began. There are six classes from X Prepared then CP to GP. These are full-out race cars built off production chassis. The concept originally began with Production- and Sedan-class road racers and most look like those type of cars. They’re highly modified, run on racing slicks, and come in on trailers because there is no way they are street-legal. CP, which is the class for Mustangs, Camaros, etc., is one of the most popular classes in the sport.
MODIFIED also has been around from the beginning but has grown to eight classes, AM to FM, plus Formula SAE and Karts. AM, BM, CM and FM are mostly formula and sportsracer chassis, including everything from homebuilt specials to full-out Formula Atlantics to wild-winged A-Mods that are almost whatever their builders can imagine. DM and EM are for wildly modified cars that began life as a production chassis. Formula SAE is the 600cc open-wheelers built to the collegiate F/SAE rules
KARTS also are technically in the Modified category but are their own animal. SCCA has Formula K, which is basically any shifter kart up to 125cc or any clutch kart up to 100 cc or so. Karters have to wear leathers or skid suits because they are the only classes that do not require seatbelts.
CAM is Classic American Muscle which consists of three classes CAM C (Contemporary), CAM T (Traditional), and CAM S (Sports). More info on CAM can be found here.