American Road Racing Series Rules

2019 rules stage V. 0.9.1

Drivers, owners and mechanics shall have no claim against or cause of action for damages, expenses or otherwise against ARRS Race Officials or Promoters by reason of disqualification or damage to either race car, driver or both.

We recommend that drivers build cars conservatively or speak with their local series directors.

1. Intent

The Intent of the American Road Racing Series, and the following rules, is to create a class that is inclusive of a variety of late model stock car chassis types, including but not limited to, late model, super late model, pro-truck, sportsman, modified, perimeter and offset type chassis that can compete in a series that encourages parity, low cost, racing skill, and sportsmanship.

A reward will be given to any driver who has shown the skill and intestinal fortitude to win in this class. If a driver is so AWESOME that he or she continues to win consecutively then they will be given an additional award. Drivers who have not yet won a race will be given some leeway.

Contact your local series director for questions on “award”  and “leeway”.

For the start of 2019 season in the NASA Rocky Mountain region “leeway” = you will only be tech’d on safety items until you win your first race. “Standard award” means that after your first win, all ARRS rules will be enforced. “Additional Award” means all ARRS rules except RPM limit changed to 5200 RPM.

2. General Overview

Competitors must assume that anything that is not explicitly stated in these rules is not allowed. Competitors should assume that any attempt to take advantage, overstep, or “outsmart” the rule set will result in a change to the rules, potentially retroactively, to bring about equality for all cars in the class. If there is any doubt pertaining to the legality of a modification or part then it is recommended that either the competitor refrain from doing so or seek clarification. If your car is better in any way than the rest of the field, expect a rule change. You might be out-driven but you will not be outspent.

3. Tolerances

There are no tolerances. The limits we have placed in this rule book already include a tolerance and are not to be exceeded, build your cars conservatively so that there is no chance that you may exceed these limits.

4. Safety Overview

All safety requirements must conform to the sanctioning bodies rules that ARRS is running with. Please carefully read and adhere to their rules and CCRs or else you will not pass tech inspections!

– Any discrepancies or single weekend allowance are at the discretion of the governing sanctioning body.

5. Chassis & Bodywork


  • Late model stockcar – tubular chassis type cars allowed includes
    • late model chassis
    • super late model chassis
    • sportsman chassis (stock front and/or rear clip)
    • perimeter or straight rail
    • modified chassis
    • 3 link and 4 link, no bird cage
    • metric chassis
    • pro-truck
    • super stock chassis (street car chassis or partial tubular chassis)
  • Purpose built, road race chassis will be allowed with adjustment.
  • * Any circle track chassis can be adapted to work in the series.

Frame & Frame Clearance

Minimum frame ride height is 4 inches, but, if a car excessively contacts the racing surface, the driver will be black flagged.


  • “Newer” car body styles are encouraged (5th gen Camaro, S197 Mustang, Challenger, CTS-V, etc).
  • Five star “ABC” style bodies are allowed.
  • Ducting may not enhance aero or downforce in any way.
  • A small, rectangle opening may be cut out of the very back center of the hood in order to allow fresh air to the carburetor.
  • Functioning brake lights are required.
  • Exterior Side mirrors are allowed.


  • All cars must have a rear spoiler that is 6.5 inches tall, 60 inches wide and placed at an angle of 50 degrees mounted on the rear of the trunk lid.
  • No under body splitters, additional spoilers/wings/canards, or any device that increases downforce beyond what the “ABC” body style offers.
  • A small pan, directly underneath the engine is allowed as long as it’s purpose only serves to protect the engine and oil pan from track hazards.


  • No in-cockpit devices that allow the adjustment of suspension, engine power, chassis, aero, or any performance allowed (only exception is mechanical brake bias adjustment).
  • Passenger seats are encouraged.
  • No aero advantage may be gained through any interior modification.

6. Weight

All cars will have a post-race minimum weight of 2800 lbs with driver.

  • Cars that are under powered from baseline will be allowed to run 4 pounds lighter per average TQ under the limit.
  • Cars that are over powered from baseline must add 16 lbs per average TQ over the limit.

* The logic behind this weight penalty/allowance is that the class baseline specs produce a car with 8 lbs/average TQ. If a car enters the series over that TQ number then they will be penalized with a weight addition double the optimal weight ratio for the class or, if they are underpowered, a weight reduction half of the optimal amount. this is to provide an incentive to produce cars as close to the baseline TQ and weight numbers as possible and eliminate the advantage of different setups for each track configuration. These adjustments are subject to change per year and with the addition of different types of chassis. Safe, LOW COST, Fun.

  • Weight is measured after timed competition sessions, this includes qualifying, qualifying races and main races.
  • Ballast must be added in block form and properly attached to the chassis, conforming to safety requirements per sanctioning body.
  • “Pellet” style ballasts are not allowed.
  • All cars, regardless of chassis type, must conform to chassis weight proportion guidelines.
  • Cars must have at least 1450 pounds of weight on front wheels.

7. Engine

Engine power output levels are derived from a stock Chevy CT400 (604) or Ford 347 SR crate motor with approximately 400HP/TQ at the crank. HP and Torque levels are expected to be ~350 @ 5200 RPM.

Any naturally aspirated (no turbos, superchargers, nitrous, etc) engine configuration is allowed as long as it meets the specified torque requirements. If you have an engine with a power adder and would like it to be included in ARRS racing, contact your local series director for a possible waiver.

Baseline engine output is 350 TQ (+/-10) averaged at 3 different RPM points (3k, 4k and 5k)


  • at 3000 RPMs  TQ is 340
  • at 4000 RPMs  TQ is 360
  • at 5000 RPMs  TQ is 357

((TQ @ 3000) + (TQ @ 4000) + (TQ @ 5000)) / 3 ≤ 352. Legal, but a little high.

EXAMPLE DYNO SHEET: If your Dyno looks like this, then you’re good to go.


DynoJet Model 248/224, 28 PSI Tire Pressure, SAE Correction, Smoothing 5, 4th gear.

*HP/TQ deviations from this baseline will result in a weight adjustment that is less optimal for performance.

All cars, regardless of motor type, will have an rpm limiter not to exceed 5400 RPMs. The limiter should begin limiting power before the limit.

EXAMPLE: soft touch rev control of 5400 kicks in at 5200 on the dyno.

ARRS may require any car to be subject to dyno or data acquisition at any time in order to confirm compliance.

8. Transmission

A maximum of 4 forward gears and 1 reverse gear is allowed. 4th gear ratio will be 1.00

The rear end ratio must not be changed during the season at the 3 Colorado tracks + MPH. This ratio must be clearly marked for tech inspection.  If driver wins a lower RPM chip then a change will be allowed.

Transmissions must be manually shifted (no electronic or assisted gearbox mechanization).

*any car that shows up with a transmission or situations that do not comply with the rules can be adjusted on a case by case basis with a performance/weight adjustment determined by the series directors until the car is fitted with components that are compliant with the rules. EXAMPLE: 5 speed transmissions may be required to run with on board video to confirm that 5th gear is not used. If there is any perceived advantage don’t expect the adjustment to be “fair”.

9. Drive Shafts

No carbon fiber drive shafts, yolks or slip yolks allowed. Drive shaft must have a minimum of two 360 degree brackets placed around the drive shaft and fastened to the floor or cross member preventing the shaft from being dislodged and dropping onto the racing surface.

10. Fuel & Fuel System

ARRS may mandate the use of a “spec” fuel at any time.

11. Suspension

Maximum track width is 80 inches for the front and rear wheels.

Maximum MSRP of shock absorbers must not exceed $200 per shock.

Only monotube, non-adjustable shocks are allowed.

  • Cars joining with adjustable shocks will not be allowed to adjust during the season.
  • Cars are only allowed to use one set of four shocks for the season.
  • Shocks replaced for damage will be allowed at the discretion of the series director.
  • No remote reservoirs shocks
    • ARRS may mandate shock valving in the future
  • A maximum spring-rate of 600lbs/in front springs and 500lbs/in rear springs.
  • 101-110 inch wheelbase is required.
  • Traction control, stability control, launch control, and/or any electronic driving assistance is strictly prohibited.
  • Any solid rear axle is required.
  • All cars must be driven only by the rear wheels.
  • Sway bars are open as long as they are not cockpit adjustable.

12. Wheels & Tires

  • Wheels must be 15 inch diameter, steel, and not of light weight design.
  • Any new 10 inch wide tires must be “firm” or “harder”, the spec tire is the Hoosier 3045 Asphalt Short Track 27.0 / 10.0-15. 
    • If a competitor is running new tires, they must also run a “New Tire Award” 5000 RPM chip to offset the new tire advantage.
    • New tires are considered tires with 8 heat cycles. This means on the 9th time a tire is used the competitor can resume using the 5400 RPM chip. If new tires continue to present a competitive advantage a “new tire award chip” may be set at 4800 RPM.
  • Any used 10 inch wide tire is allowed without the need for the “New Tire Award Chip”.
  • A driver must compete for the entire weekend on the tires used for the first qualifying session. If a tire is damaged it may be replaced. If a driver can not compete an entire weekend on a single set of tires they must add 100 pounds adjustment weight to continue.
  • 12 inch wide used tires are allowed with a 50 pound weight adjustment. A driver must compete for the entire weekend the tires used for the first qual session.  If a tire is damaged it may be replaced.  If a driver can not compete an entire weekend on a set of tires they must add 100 pounds adjustment weight to continue.
  • Any 8 inch wide tire is allowed.
  • Drivers must inform the series director of their tire choice as soon as practical.

13. Brakes

  • Brakes calipers and pads are open.
  • ABS devices are prohibited.
  • Brake ducting is allowed.
  • Brake fluid re-circulation is allowed.
  • Brake fluid coolers are open.

14. Protest

We recommend talking to the competitor about it first before telling everyone else that they are cheating. After that please bring your concerns to the local series director.

  • Random tech inspections can and will occur on any/all cars at any event.

15. Sportsmanship & Conduct

This is our hobby… we do this for fun. It is each driver’s responsibility to promote fun, encourage ARRS class growth, and ensure that crew members, family, friends, pets and anyone who knows you conform to the highest standards.