2021 HMSA Rules — Download PDF

We wish to establish a clear understanding of the “point in time” (i.e., 1932, 1965, 1967) to which a car is restored.  Modifications which are not in keeping with that “point in time” are not allowed.  Modifications which improve a car’s performance and are beyond the stated “point in time” are not allowed.  Non period modifications such as modern valve train replacements (roller rockers, roller lifters, etc.), non OEM aftermarket headssingle plane manifolds, air-gap dual plane manifoldsJericho gearboxes or gear sets, vented discs, aftermarket/non period brake calipers, traction control like devices, spoiler or splitters etc. are not acceptable!  Replacement components if allowed must be manufactured of the same material as the OEM component. If you are not sure if it’s legal, ask

ENGINE:  The engine must be of the original type and specifications as homologated when the car was produced.  Displacement, carburetion intake manifold and valve train must be original in specification, configuration, and material. HMSA will perform random testing of displacement, by bore and stroke dimensions or volumetric testing. The valve train may be inspected physically or via bore scope. The valve train will be inspected to verify that non-roller lifters and non-roller rocker arms are fitted where applicable.

WHEELS:  Cars must run on wheels of the same type and size as were made available from the manufacturers at the time of production,  aftermarket equivalents of period design are acceptable.  We refer specifically to rim width, diameter and off set as specified in the manufacturer homologation statement. A maximum of .5″ increase in rim width is allowed. In certain instances for safety reasons the offset of wheels may be altered.  Requests should be made to the HMSA office in writing. Wheels must be free of cracks and faults. Have them crack tested bi-annually at a minimum.  Spokes must be properly tensioned.

Bolt on Rudge Whitworth Spline adapters must have a paint strip on their retaining fasteners indicating the adapters are secure.

BRAKES: Dual brake circuit master cylinders are recommended.

BODY:  All body panels must be of the original material type and adequately fastened. Body modifications from original such as contemporary flares, body ventilation holes, spoilers, splitters and/or air dams will not be accepted.

ADVERTISING ON CARS:  Only historically correct markings are acceptable.  Modern advertising is not allowed.

PRESENTATION: Cars must be presented in a neat and finished condition.  Engine compartment, suspension, chassis and drive line must be clean enough to facilitate inspection.  Cables, wires and hoses must be taped or otherwise secured to prevent chafing, etc.

CATCH TANKS:  A securely fastened radiator catch tank with a minimum capacity of 1 qt. is required.  An additional catch tank should be fitted on engine oil breathers where practical.  Cars showing indications of oil loss through their breather system will be required to fit a catch tank. No oil, fuel, water or fluid leaks of any kind will be tolerated.

COOLANT:  Use of water rather than coolant is required.  Glycol based coolant is not allowed. Water wetter type products are allowed.

THROTTLE RETURN SPRINGS: A minimum of two (2) system external return springs are required in addition to the original overall system linkage spring. Springs on/in the body of carburetor do not count as external return springs. Fuel injection systems must have a backup (secondary) return spring in addition to the overall system spring. Primary springs can not share the same mounting point with back-up springs. Each external spring requires a separate mounting point unless approved by an HMSA Tech official.

SEAT BELTS:  All cars equipped with a roll bar must be equipped with racing type seat belts of nylon web, at least 2″ in width lap belt. Both lap and shoulder belts having metal to metal buckle. Belts must be securely mounted to the frame. Replacement is required at manufactures expiration date or 5 years from date of manufacture which ever occurs sooner. All belts must have an SFI or FIA label with the manufacture date or expiration date affixed to the belt set. IF THEY DO NOT, THEY ARE VOID AND MAY NOT BE USED.

SHOULDER HARNESS: If shoulder harnesses are used, they must not be a “Y” type belt type. It is highly recommended that each shoulder harness have its own mounting point for each shoulder belt. If a Head and Neck protection system is used, 2″ shoulder belts are allowed otherwise, 3” belts are highly recommended. Replacement of belts is required at manufactures expiration date or 5 years from date of manufacture which ever occurs sooner.

ROLL BARS:  Roll bars are very strongly recommended. FIA or SFI spec high density foam is strongly recommended in areas which the driver  may make contact in the case of an incident.

MIRRORS: Very useful! At least 1 rear view mirror with a minimum area of 8 sq. inches is required.

WINDOW NETS:  If the car is fitted with a window net, it must be used.

FIRE EXTINGUISHERS:  All cars must be equipped with a 2 lb., 10 BC (or Halon equivalent) fire extinguisher securely mounted with a metal bracket and metal retaining strap, plastic brackets and retaining straps are not acceptable.. Hand held extinguishers should be within reach of the driver. An onboard fire system is strongly recommended. If so fitted, verified by a gauge or other method, that they are full and operational prior to each event.

ELECTRICAL CUT-OFF SWITCH:  It is recommended that each car have a master electrical cut-off switch fitted outside the car and be clearly marked. ALL terminals and connections are to be covered with an insulating material.

FUEL CELLS: are strongly recommended. If a fuel cell is used it should be an approved soft bladder type not a rotational mould plastic box. Fuel cells must be securely mounted to the car in a metal containment vessel. All fuel cell bladders must have foam inside. It is highly recommended that Fuel Cells be inspected annually for signs of bladder and foam degradation. Fuel cell bladders have a specific usable lifespan from date of manufacture, consult your cell manufacture for your cells recommended lifespan.

FUEL CELL CHECK VALVE: If a fuel cell is used, a one way check valve in the vent must be used. The check valve tube must be vented to the exterior of the car.

ALL FUEL FILLER CAPS: Must be securely fastened so as not to open on impact.  Monza type (quick release) caps must be wired shut.

A FIREWALL: Must exist between the cockpit, engine and fuel tank. It must be free from holes. Selected Formula cars excepted.

UNDERTRAYS: Must have drain holes.

SUSPENSION PARTS:  It is strongly recommended that suspension parts and steering components be crack checked bi-annually. Three of the most common methods of inspecting material integrity are; Magnetic particle inspection, chemical dye – penetrate and x-ray. No part of suspension shall have excessive play. Any suspension part installed and secured in single shear, particularly spherical rod ends (Heim joints), must include a captive washer of sufficient diameter to retain the entire component at the mounting point. Suspension mounting points are to be in the original position and location.

STEERING: No part of the steering assembly shall have excessive play.

BRAKE SYSTEM: Brakes, lines, fluid, pedals must be in good operating condition. Dual brake circuit master cylinders are recommended. Brake calipers are to be as originally fitted to the car, in piston bore size and manufacturer. Drilled, slotted, 2 piece and or vented brake rotors are not allowed unless originally fitted to the vehicle at time of manufacturer.

BRAKE LIGHTS: All cars must be fitted with at least one brake light in working order.  Open wheel cars are exempt from having brake light(s).

CAMERAS: The mounts for video / photographic cameras shall be of a safe and secure design. The body of any camera or recording unit that weighs more than 8 oz shall be secured at a minimum of 2 points. All cameras, including “Go-Pro type”, must have a secondary method (tether) of retaining the camera body, not the camera mount, to the vehicle. Cabled Lipstick cameras are exempt. All cameras must have a camera tech sticker affixed for each event. Any cameras mounted to the exterior of a car with anything other than a solid mechanical connection shall have a secondary tether. (Cameras mounted with suction cups, Velcro, and/or tape will require a secondary tether.) Additionally camera mounts with plastic arms shall have a secondary tether. Helmet-mounted cameras shall not be allowed. 

Any cameras mounted to the exterior of a car with anything other than a solid mechanical connection shall have a secondary tether. (Cameras mounted with suction cups, Velcro, and/or tape will require a secondary tether.) Additionally camera mounts with plastic arms shall have a secondary tether. Helmet-mounted cameras shall not be allowed.

DRAIN PLUGS: All drain plugs must be safety wired.  In certain cases, where it is virtually impossible to wire the sump plug, the tech inspector may approve a paint stripe.

BATTERIES: Must be securely fastened down.  All of the positive electrical contacts, connections and terminals i.e. battery, regulator, generator, alternator and some starter terminals must be covered with an insulating material to prevent grounding.  Batteries located in the cockpit must be in an enclosed, covered container or have leak/spill proof caps.

CAR RACE NUMBERS:  All event numbers will be assigned.  Numbers should be 2″ – 3″ in width and 14″ – 15″ in height and in a contrasting color from the background.

TOW HOOKS: It is required that all cars have an eyebolt or equivalent front and rear to attach a tow cable. The location point must be clearly marked.

TIRES: The BASIC TIRE RULE governing acceptable tires for each car:
Tires must approximate as closely as possible the dimensions of the tires originally available on the car at the time of manufacture. This refers specifically to diameter, cross section and tread width. (The size indicated on the side of some current tires does not mean that the dimensions of the tries are the same as an original tire with the same listed size). Hoosier Speedster tires are not acceptable.

TREAD PATTERN: All tires must have a tread pattern of period design. If hand grooved, the tire must have the correct number of groovesas originally grooved by the supplier/manufacture, i.e. Avon historic pattern.

COMPOUND:  Tires must be of a manufacturers “Hard” compound.

CLASS TIRE REQUIREMENTS are listed.  There may be some individual tires that may also approximate original tires for a specific car.  These might include a 70 series radial tire.  A request to use such tires will be considered if they are truly appropriate.


ClassCar TypeTire

A-11900-1926 Sports & Racing CarsFREE

A-21927-1939 Sports CarsFREE

A-31929-1939 Racing CarsDunlop 204 L/Blockley

A-41946-1954 Grand Prix CarsDunlop 204 L/Blockley

B-11947-1955 Sports Cars (GT)Dunlop 204 L/Blockley

B-21947-1955 Sports Racing Cars Under 1500ccDunlop 204 L/Blockley

B-31947-1955 Sports Racing Cars Over 1500ccDunlop 204 L/Blockley

C-11955-1960 Sports Racing Cars Under 2000ccDunlop 204 L/Blockley

C-21955-1959 Sports Racing Cars Over 2000ccDunlop 204L/Blockley/Michelin Pilote X

D1959-1965 Sports Racing CarsDunlop 204L/Dunlop 204M/Goodyear

E-11955-1957 Formula I-IIDunlop 204 L/Blockley

E-21958-1963 Formula I-IIDunlop 204 L

E-31958-1963 Formula Jr.Dunlop 204 L

FF1967-1972 Formula FordDunlop or Avon ACB9 treaded

G-11955-1961 GT Cars Under 2000ccDunlop 204L /Goodyear /Hoosier*/Avon*

G-21956-1962 GT Cars Over 2000ccDunlop204L/Goodyear/Hoosier*/Avon*

G-31962-1965 GT Cars Under 2000ccDunlop204L/Goodyear/Hoosier*/Avon*

G-41963-1965 GT Cars Over 2000ccDunlop 204 L/Goodyear/Hoosier*

I1965-1972 FIA Makes Championship CarsGoodyear /Avon /Hoosier

T-A1966-1972 Historic Trans-Am CarsGoodyear 600×15 / 700×15

* = Hoosier Vintage TD upon Approval

G-1, G-2: 1955-1962
G-3, G-4: 1962-1966
Interior: Interiors are to be installed and as original fitted by the manufacturer.

  1. Modifications to the interior that reduce the weight of the car are not allowed, with the following exceptions:
    1.  Floor mats or rugs may be removed.
    2.  Window glass may be removed from doors.
  2. The removal of interior trim (gutting) is not permitted.
  3. The cars must have 2 seats (original and/or period bucket seats is allowed), original dashboard (you may exchange or add instruments), interior door panels.
  4. Installed safety equipment, such as roll bars or roll cages may not have any influence on the mechanical performance or handling of the car


  1. Tops may be removed from open cars. Soft tops are not allowed.
  2. Bumpers may be removed, but if so, all projecting hardware such as brackets must also be removed.
  3. Grills may not be removed.
  4. Windshields may be replaced by a suitable windscreen.
  5. Lighting equipment must remain in place.
  6. Headlights and other glass lenses on the vehicle should be covered or taped.
  7. All exterior trim must remain in place.
  8. Window frames must remain in place.
  9. Rigid, not originally fitted passenger cockpit coverers, (tonneau covers) are not allowed unless originally fitted in period.

Must be of the original type and specifications as homologated when the car was produced. Steel braided brake lines are allowed. Driver adjustable brake proportioning valves within reach of the driver are not allowed, unless originally fitted to the vehicle.

Must be original as stated in the general HMSA rules. Modern valve train replacements such as roller rockers, roller tip rockers, roller tappets or lifters, titanium valves, etc. are not allowed.   Dry sump systems that were not originally fitted to the specific car are not allowed.  Headers are allowed.

Transmission, Clutch & Differential:
Must be of the original type, as produced by manufacture. No after-market cases or internal gear sets unless they are of the same OE type replacement. Gear ratios as originally offered.

Minimum Weight: 
The minimum weight allowed is that listed in the SCCA Rule Book, Production Car Specifications, 1962 for G-1 & G-2 and 1965 for G-3 & G-4, less 7%.

Ignition: Points or internal electronic triggering within the original distributor is allowed. No external ignition triggering of any type is allowed, unless it was originally fitted at time of production. No external spark enhancement devices are allowed unless produced and allowed originally in the point of time for the car’s acceptance date. No device may be attached to the system which results in traction control. An external ignition box (MSD, Crane, etc.) may be used, as long as the system is operated within an OEM (period) distributor. Any ignition system may NOT offer traction control.  If an external ignition box is used, it must be located out of normal view where it cannot be seen. Any competitor found with any form of traction control, within the ignition system or otherwise, will be permanently excluded from HMSA and/or SCRAMP events.  


Car Verification and eligibility:
Only cars that actually competed in NASCAR’s Grand National or Winston/Nextel Cup events thru 2006 are eligible. No COT or newer cars are eligible. Cars must be carefully prepared and presented to “a point in time” (see car preparation). Cars will be inspected, weighed, and verified at the first 2 events of the year. Any deficiencies will be noted, and MUST be brought into compliance before the participant’s next planned event. Each car will receive an annual ‘compliance’ sticker. This does not replace the tech inspection at each event, but is, initially, supplemental to it.

Car preparation:
Cars presented for entry must be homogenous with respect to body design, paint, graphics, and mechanical components. Chassis, body configuration and engines must be from the same year.

Cosmetic preparation:
Cars must be consistent in appearance with the year in which they ran in NASCAR. Paint and graphics should reflect the “point in time” year stated. Historic photos or other archival documentation is required.

Safety preparation:
Proper driver attitude and conduct are essential to on-track safety, and are covered elsewhere in the rules. With respect to car preparation, an adequate, and working, 3-nozzle fire system is required, with an engine, driver, and fuel tank nozzles. Visibility in these cars is often limited, thus, 3 mirrors (left, center, right side) are required.

In an effort to equip all cars with similar braking power, front brakes calipers must be of a make and model available to the year as determined by the “point in time” selected for your car. The addition of modern brake components are not allowed.

Wheels and tires:
Wheels must not exceed 15 inch diameter or 10 inch width. Tires are specified as Goodyear Stock Car Special-bias ply (part # 1439) unless otherwise noted.

Vehicle weight:
Vehicles must weigh a minimum of 3600 pounds, with driver and fuel.

Engine preparation:
This is not the place to test yours, or your motor builder’s talents and expertise. Engines must be configured and prepared exactly as they were for the “point in time” year of car. Displacement is limited to 358 cubic inches. All cars are subject to displacement verification (“pumped”) and random checks will be done. Carburetor is a single Holley 850 cfm on a period-correct (“point in time”) manifold. Cylinder heads: Chevrolet-up to and including “18 degree” cylinder heads and SB2 cylinder heads of a design and manufacturer consistent with the year of car they are in. Pontiac “867” cylinder heads. Ford-Ford “C-302” and early “Yates” heads, C3 and C4 Ford heads of a design and manufacturer consistent with the year of the car they are in.


This group was formed to showcase 1980-1991 IMSA GTO and 1980-1991 SCCA Trans-am cars. The cars of this era represent a significant piece of Motorsports History. Our mission is to encourage restoration and preservation of this group of cars. The objective is to provide an opportunity to,” Let your car be the star”. There are a lot of fans who want to see these cars race. There is the expectation that the cars are to be prepared period correct. It is important to race and show the cars as they were, not as what they could be; modified with the latest technology. The drivers are not the focus, it is the cars. This has been said before but it is very appropriate,” The history of these cars has already been written”. We want to give you an opportunity to present it.

Group Guidelines

  1. The cars must have history of competition in either IMSA GTO or SCCA Trans-am or both. To qualify for the Group, the car must have run at least four races at four different tracks in a 12 month continuous month period. A DNF counts as long as the car qualified for the race. The four races can be a combination of Trans-am and IMSA GTO events. The entrant will be responsible for submitting a supported qualifying “Line of Race History”, to be considered for entry in events.
  2. The car will need to have a verifiable and substantially continual chain of ownership. The owner must be able to prove the heritage from the year the car was built to present day. The owner will need to state the point in time the car is restored to, and who was the driver at that time. Proof will be in the form of period race reports, photos, chassis number, year of construction, and the name of chassis builder. Additional proof can be documents from prior owners or drivers, magazine articles, race results, etc. 
  3. The car must present well. Current photos should show to what “point in time” it is restored. Mechanically as well as the livery. It can be a nicely restored car or a significant survivor with a patina of age as long as it appears “today” exactly as it did during the “point in time” represented.
  4. The “point in time” is defined as: the car is correctly restored to as first raced or restored to a special event in its history, at the owner’s discretion, such as having won its class at Daytona. In such a case, for example, it is possible that a 1984 chassis car might be configured and painted as run in the 1988 Daytona 24 Hour but in no case later than the 1991 “point in time”. The car will need to have period correct paint scheme, graphics, decals, wheels etc. Current sponsor decals or graphics will not be allowed.
  5. The cars must be correct as to engine spec, size, weight, wheel size, brake rotor diameter, differentials, suspension, roll cages and so on. No modifications are allowed. No Radial tires are allowed. All tires used will be Bias ply hard compound construction. In the case where the car was originally designed and raced with radial tires in its 1st race season, an appeal may be made to allow radial tires. The car is expected to meet the rules from the series and the year to which it is restored.
  6. Th­e range of engine size, horsepower, and weight of the cars are going to makes it difficult to strike a balance, of the various cars performance within the grid as this group covers a number of years spanning two different series. As such, the races will naturally break into several smaller “packs” where the drivers can have wonderful tight racing. Everyone is encouraged to “hook up” with a group as this is more enjoyable for the drivers as well as the spectators than a single car running by itself. The grids will be set by qualifying times.
    This group is made up of a diverse group of drivers with different levels of experience and talent. These are cars that require a certain level of skill. The drivers are expected to have the experience, competence and common sense to drive one of these cars safely. If you are found to be driving in an unsafe manor or if you do not adhere to the philosophy of the group, the group will take appropriate action. If you can not agree with this type of philosophy, then this may not be the race group for you. 
    The objective is to promote a race group where entrants will bring out very significant cars and feel comfortable racing at their level and sharing their car with the public as the cars were intended. In addition to providing the drivers a great driving/racing experience, the goal is for the spectators to come to the paddock excited and witness great close race it was, just like it was back in the day.

Formula Atlantic Supplemental Regulations

Years of eligibility: 1971 – 1979

Approved engines (basically saloon car steel block):

Alfa t/c; BMW 1.6 SOHC; Fiat 124 DOHC; Datsun 1600 SOHC; Cosworth BDA & BDD
Ford, 1500, 1600 pushrod t/c Porsche 1582cc Renault 1600cc TS

Maximum bore: 81.5mm (1606cc)
Stroke: 77.6mm
Oversize engines will be addressed on a case by case basis.

Fuel Injection not allowed

Minimum weight 1050 lbs (If using aluminum block the minimum weight will be 1110 lbs.)
            All competitors should arrive at the track with ballast and a safe way to mount it to the car.

Max 5 forward gears

No ground effect side skirts allowed
No ground effect tunnels

Wings original positions, same type (element number) period profiles

Front wings
Front wing leading edge airfoil radius =.6″ (1.5cm). 
Bodywork or aerodynamic devices (wings) in front of the front tires shall not exceed 59.055″ (150cm).

Rear wings
Rear wing width = 110cm – 43.307″
Rear wing set-back = 39.4″ from CL of rear wheel to end of rear wing
Rear wing height = 34.5″ measured on a horizontal plane from the ground w/o driver

No Carbon/Kevlar composite body panels

Shocks: Non-pressurized shocks maybe double adjustable 8212 KONI or Bilstein
Pressurized shocks shall be non adjustable
No remote reservoir allowed

Tires: Avon A11 and Goodyear tires are acceptable.

Clutch pack to be no smaller than 7.25 inches. Driven plates must be centered metal. They can be nested or stacked.

Penalty for any infractions should be weight at Stewards discretion.