Class rules 2026

Presentation of class rules for Street Week 2026.(Download as pdf)

Adjustments and clarifications of class rules for 2026.

Ultimate Street, True Street & Import War
Back Half:See specific reference to the definition for Street Week at the bottom of the document.

Pro Touring
Four-point suspension:A specification has been added for measuring parallel struts.
Rear axle suspension:Clarification regarding the original k-link rear axle suspension where lift kits are allowed (for example, Chevrolet Chevelle 1968).

Max Outlaw

- The maximum protrusion for front body extensions is 1000 mm measured from the center bolt of the front hub.
- Everything else is free.

Street Outlaw

- Slicks factory marked with max 10.5” W
- Patterned, factory marked with max 315
- The maximum protrusion for front body extensions is 1000 mm measured from the center bolt of the front hub.
- Everything else is free.

Ultimate Street

- Body from a mass-produced car
- Windshield type original, safety glass, material free in other windows.
- The rear screen edges can be stretched, widened.
- The hood, front fenders, trunk lid, and bumpers may be made of a different material than standard.
- Flip front approved as long as it resembles the original and meets other requirements.
- The grill should resemble the original, it must not be blocked from the outside with a solid cover.
- Back Half. See definition of Back Half at the bottom of the document.
- Wheelie bars allowed.
- Front spoiler may be installed.
- Any rear wing should follow the body if the car is not equipped with a standalone.
wing as standard, then a standard-like wing can be mounted.
- Unmarked slicks not allowed.
- Gatslicks allowed.
- Optional tire size.
- Other tire, see footnote.
- NOT 4WD
- Front body extensions (beam breakers) are prohibited.

True Street

- Body from a mass-produced car
- Windshield type original, safety glass, material free in other windows.
- The rear screen edges can be stretched, widened.
- The hood, trunk, and bumper may be made of a different material than standard.
- The grill should resemble the original, it must not be blocked from the outside with a solid cover.
- Back Half. See definition of Back Half at the bottom of the document.
- Wheelie bars not allowed.
- Front spoiler may be installed.
- Any rear wing should follow the body unless the car is equipped with a standalone wing as standard.
then a standard-like wing can be mounted.
- Unmarked slicks not allowed.
- Gatslicks allowed with a maximum width limit of 295. Max 16” rim diameter.
(If only thumb measurements are available on the tire, then 10.6” tread width is the maximum)
- Other tire, see footnote.
- NOT 4WD
- Front body extensions (beam breakers) are prohibited.

Pro Touring

- Body from a mass-produced car or a copy of it.
- 17” or larger wheels, front and back.
- Unmarked slicks not allowed.
- Gatslicks allowed.
- Other tire, see footnote.
- No tube chassis cars intended for drag racing.
- For a four-link suspended rear axle of non-original type, the rods must be parallel within ± 10 mm. This is measured at the vehicle's ride height when presented on the racetrack.
- With the original k-link rear axle suspension, lift kits are allowed, for example, Chevrolet Chevelle 1968.
- NOT 4WD
- Front body extensions (beam breakers) are prohibited.

4WD

- Engaged and functioning four-wheel drive is a requirement during the time trials.
- Verification that 4WD is engaged must be presented if SWS staff requests it.
- Body from a mass-produced car, including the main part of the floor & firewall.
- Windshield type original, safety glass, material free in other windows.
- The rear screen edges can be stretched, widened.
- The hood, front/rear fenders, tailgate, and bumper may be made of a different material than standard.
- The grill should resemble the original, it must not be blocked from the outside with a solid cover.
- Front spoiler may be installed.
- Wing at the back can be installed.
- Unmarked slicks not allowed.
- Gatslicks allowed, marked by the factory with a maximum measurement of 26”
(with measurements in millimeters, the manufacturer's specified maximum height of 668.02 mm)
- Performance tires of R-type and standard tires free height and width.
- Other tire, see footnote.
- Front body extensions (beam breakers) are prohibited.

Import War

- Six or fewer cylinders as well as Wankel.
- Body from a mass-produced car, including the main part of the floor.
- Windshield type original, safety glass, material free in other windows.
- The rear screen edges can be stretched, widened.
- The hood, front/rear fenders, tailgate, and bumper may be made of a different material than standard.
- The grill should resemble the original, it must not be blocked from the outside with a solid cover.
- Back Half. See definition of Back Half at the bottom of the document.
- Free execution of the torpedo wall, the valve cover should be located in front of the lower edge of the windshield.
- Front spoiler may be installed.
- Wing at the back can be installed.
- Unmarked slicks allowed
- Maximum height of the tire is 28” (when measured in millimeters, the manufacturer's specified maximum height is 711.2 mm)
- Other tire, see footnote.
- NOT 4WD
- Front body extensions (beam breakers) are prohibited.

Two separate classes apply in Import War.

- Front-wheel drive
- Rear-wheel drive

Diesel Power

- Fuel requirements Diesel
- Max 3500 kg curb weight.
- The registration certificate determines the weight.
- Exhaust pipes are directed away from the asphalt.
- Unmarked slicks not allowed.
- Gatslicks allowed.
- Other tire, see footnote.
- Front body extensions (beam breakers) are prohibited.

Classic

- Body type 1949-1959
- No tube chassis cars.
- Unmarked slicks not allowed.
- Gatslicks allowed.
- Other tire, see footnote.
- NOT 4WD
- Everything else is free.
- Front body extensions (beam breakers) are prohibited.

Hot Rod

- Body type up to 1948
- Unmarked slicks not allowed.
- Gatslicks allowed.
- Other tire, see footnote.
- A time under 6.5 seconds/201 m is automatically disqualified.
- NOT 4WD
- Front body extensions (beam breakers) are prohibited.

Definition Back Half for Street Week

- From the rear edge of the front seats and backward, there is free modification of the chassis.
- From the rear edge of the front seats and forward, the floor and frame must be standard and positioned in the standard location; holes may be made for chassis tubes/reinforcement tubes. No smooth floors of non-original type are approved.
- The driveshaft tunnel can be widened/lifted, but the floor must be in one piece and in the original position; a removable cover over the gearbox is not allowed.
- The torpedo wall must be original and in its regular place; certain modifications may be made, but absolutely not with the intention of moving the engine package backward. The location for the heating package may be replaced.
- Inner fenders may be removed, original frame rails must extend all the way forward, the beam between the frame rails may be modified/removed.
- Loose aftermarket frames that replace the original frame rails are not allowed.
- The original front suspension type should be there, control arms can be replaced but must have the same mounting position as the original.
- You may replace the standard spring with coilovers, some modification of the shock absorber mounting is permitted.
- The steering rack can be replaced by a rack and pinion.

Certain exceptions exist, see separate class rules.

Footnote:

Gatslicks: Has a manufactured pattern of at least two circumferential grooves in each tire, as supplied by the manufacturer.
Performance tires of R-type and standard tires have regularly recurring patterns in manufacturing as delivered by the manufacturer. The performance tires described above are classified as street tires.

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