Deviations from the Mopar Mountain Modifieds rules will be highlighted in red.


The following document outlines the Modifieds rules for club racing in the Western Pennsylvania Slot Car Club.

This division follows the “NASCAR Featherlite Modifieds” class run in the Permatex 300 for Modifieds (1960s era) and other Modifieds events at Mopar Mountain Motorplex, with several deviations for local racing.

The rules are written with the intent of providing a precise specification that will define each car’s construction. It is fully expected, and in fact intended, that the racers will adhere to these rules as they design and build their cars. Any breach of these boundaries will result in the disqualification of the car.

General Class Information

1. This class is designed to be run on oval track banked at 6-9 degrees.

2. Timing & Scoring: computer lap timing system preferred.

3. Power standard: 18 Volts.

4. Controller: Any Controller may be used (no boxes). Brakes and/or brake hook-ups may not be used.

5. Qualifying will be used to determine starting order (5 laps)

6. Each driver will run one heat in each lane, with each heat lasting 4 minutes.

7. There will be no track calls during the race. All car repairs and maintenance must be done under the green flag only. If indicated, the race format can be individualized to reach the expected lap total.

General Car Information

1. The combined chassis and body shall weigh between 18 and 21 grams.

2. The car shall not exceed 3 inches in length.

3. The car shall pass freely through a 1 5/16” tech block.


1. Legal chassis include the following: original Aurora brand Thunderjet/Tuff-Ones, JL/AW Thunderjet 500 or Model Motoring Thunder Plus.

2. The chassis shall remain unaltered except in the instances noted below.

3. The vertical gear plate rails located on top of the plate may be trimmed for body clearance purposes.


1. Any American late model, coupe, coach, or flatback body may be used. No trucks, foreign, or sports car bodies may be used.

2. Bodies may be injection molded or resin cast.

  • • Posts may be added to an acceptable body provided that they utilize the existing stock mounting location for posts.
  • • Bodies may be lowered and lightened. There are no lowering restrictions except that the roof and drivers compartment must be intact.
  • • Front Fenders may be removed.
  • • Rear Fenders may be trimmed and hollowed out.
  • • Glass may be removed.
  • • Trim pieces may be added to achieve a look of authenticity (i.e. side exhaust pipes, wire mesh or screen for windows, spoilers, etc.)
  • • Examples of acceptable bodies may be viewed at the following websites:


1. Magnets shall be any readily available ceramic. These include the following most commonly used, but are not limited to, JL (blue & white), Super 2 (blue & yellow), or AFX Non-Magnatraction (blue & red).

2. Magnets may be shimmed by the use of non-ferrous materials only.

3. Magnets may be shaved to enable proper fitment in chassis.

4. No other magnet modifications shall be allowed.


1. There are no restrictions on gears.


1. Armatures may include T-jet, AFX, Tuff-Ones, JL, Mean Greens, blue drag.

2. Armature commutator plates may be cleaned and/or polished.

3. Armatures may measure an average of no less than 5 ohms from pole to pole.

4. Armatures may be balanced by means of removing material from the poles or by adding weight with epoxy or super glue.


1. Any readily available pick-up shoe shall be legal. The step or contact patch shall remain unaltered.

2. Any method may be used to limit pick-up shoe travel.

3. Pick-up shoe springs shall be an original Aurora part or an identical replacement (i.e. BSRT).

4. Pick-up shoe springs may be trimmed, stretched, or used as shunts.

5. Any copper/carbon composite brush shall be legal.

6. Shunts may be used to improve electrical conductivity.

Wheels, Axles, & Tires

1. Any readily available hub/wheel may be used. Wheels may be lightened.

2. Only readily available slip-on tires may be used (no sponge silicones).

3. Any readily available axle (rear) and weighted fronts may be used.

4. Each tire may measure a maximum of 0.400” O.D. There is no minimum tire size restriction. All four wheels must touch the track.

5. Glue/adhesive materials may be used to secure tires to wheels.

6. No specially fabricated or freak parts (i.e. spring loaded axles) may be used.

Revised 1/30/2010