Rule Changes 2024 Season

Transponders are mandatory for the beginning of the season.


  • 600 Class American Racer Spec Tire or U6SA or ASCS2 Stamped Hoosier Right Rear MANDATORY. NO doping of tires. The tire must durometer more than 45.
  • Each racecar shall have four (4) tires and four (4) wheels. The wheels shall be made of steel, aluminum, or carbon fiber, and be 10 inches max in diameter. The tires shall be unaltered except for grooving, grinding and sipping. NO RECAP’S OR TIRE SOFTENERS SHALL BE ALLOWED.
  • At any time GSMS board members can ask for tire to be dismounted to check for tire softeners.

450 engines will be allowed to race in the 600 class for no points and must start in rear for both heat race and feature.

Electric fuel pump safety relay must be installed on all cars equipped with an electric fuel pump, including lift pumps for Mechanical Fuel Injection Systems This relay must automatically shut off the electric fuel pump when the engine stops running.

600 engines aftermarket coils are allowed.

New line ups for point races.

1st race pill draws to start heat races,
Heat race results will be feature line up.
After heat races there will be pill draw to invert how many cars will be inverted, up to 10 positions for feature line ups.
Lineups after the 1st race,
The heat race order will be by lowest points to the front and highest to rear.
The previous week’s winner will start in rear for heat race in front of rookies and temporary members.
Feature lineups will be based on heat race results.

Inverts after heat races.

After heat races there will be pill draw to decide how many to invert 1-10 position for feature line ups.
If a driver misses a week of racing, this driver will start in the rear of the field the next race the driver attends. If the driver is not a rookie, the driver will start ahead of the rookies if within the first three-week rule of a rookie’s season. At the second consecutive start the driver will line up based on points.
If a driver wins a feature race, they will start last in the field the next race. Should there be missed races in between the feature race win and the next race start, the driver will still be expected to start in the rear of the field.

400cc / 500cc Rules

As of 2026 only engine allowed to race will be the Honda 420cc
Age limit 11 years old with race experience, 12 no racing experience


420cc Sealed Engine Rules:
Maximum displacement 420cc
Stock cam or Hot cam part# 1007-1
36mm Mikuni flat slide carburetor.
Must be sealed at owner’s expense.
Robbs Racing Engines.
New England Kart Center.

420cc Modified Engine:
Maximum displacement 420cc
Any cam.
Any size carburetor.
Any exhaust system is allowed if it incorporates a muffler.

specifications. PORTING or POLISHING only for 420cc modified.

Any cylinder head is allowed if manufactured to OEM.
Any camshaft, cam gear, timing chain, valves, valve springs, retainers, keepers, guides, and valve seats may be used. Any size valve may be used but MUST fit stock seat.
500cc Engines must use restrictor plates, the club will provide one to each driver.


400cc / 500cc

Required Weight:

  • 420EX Modified Motor Models
  • Weight: 725 lbs.
  • 420Ex Sealed Motor
  • Weight 625lbs

500cc Motor Models

  • Flat type Piston 725lbs.
  • Dome or Fly Cut Piston 725lbs.


  • If you are involved in a yellow flag incident during any lap, you shall be placed at the field’s rear.
  • If you are involved in 3 yellow flag incidents, you are black flagged for the event.
  • The Board reserves the right to inspect cars after incidents on the track.

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About GSMS

Granite State Mini Sprints (aka GSMS) is a non-profit, family-oriented organization dedicated to the enjoyment of mini-sprint racing whose members compete in cars utilizing motorcycle engines and drive components. Their specifications are restrictive to emphasize driver ability rather than design or preparation of the car.