ISMA / MSS Rules Survey

In the fall of 2022 ISMA President formed an 8 member rules panel made up of two owners from Oswego, ISMA and MSS organizations, a Chairman and a Scribe.  The Rules Panel goal is to bring the rules of the 3 organizations closer making it possible for construction of supermodifieds that would be legal at Oswego and the newly formed ISMA/MSS. 

After identifying several rules to be discussed the 6 panel (2 from each organization) engaged in an open discussion on how to create a rule that had the least impact on current supermodifieds, minimize costly changes, and determine if there is a significant if any performance advantage.  The rule was then drafted by the scribe, sent to the 6-panel members to review, and approve.  The following are the proposed rules for owner members to approve or reject.

If you choose to reject the proposed rule, please write a constructive comment that could help steer the discussion that could ensue.

Car Owner Information


Streamline tubing is permitted, but can’t be used for diagonals or cross-members in the main structure (center section). Below is a chart that will help enable you to choose the correct streamline tube size. The wall thickness in this case is only an example, but the comparison would be the same if the wall thickness you choose is thicker.

It is recommended that you err on the side of caution when considering the use of streamline tubing. as bending strength about the major and minor axis are considerably different. The minor axis having considerable lower bending (buckling) strength than the major axis. This means you should only consider using this if you fully understand your suspension loads and consult with someone who has used it.

**** Items besides Helmets, hans, etc., (safety equipment) should be brought to the rules committee to ensure rules compliance if there is questionable devices. *************

Carbon fiber components are allowed only to provide for driver safety. Carbon fiber cannot be used in place of metal for body panel or chassis construction.

- Maximum of one shock absorber per wheel.

- Maximum of two adjustments on the shock absorber.

- No inerter, thru shaft or rotary valve shocks are allowed.

- Any shock canister is allowed.

- Maximum cost per wheel is $1500 retail price and the shock must be available to any competitor at that price.

DRIVE LINE -- The drive line shall run directly from the engine to the rear end. No transfer case assemblies, clutches, transmissions, in/out boxes, or hydraulic couplings of any kind will be allowed.

a) The driveshaft shall be made of steel or titanium only and be painted white for ease of visibility.

b) Conventional drive shafts using cross and yoke assemblies (Cardan assemblies) shall meet the following requirements. Slip yokes are to be made of steel or aluminum. Steel is highly recommended. Medium duty (Series 1350) universal joints with solid cross are highly recommended on both ends of the driveshaft.

c) Drive shafts utilizing constant velocity joints (CV joints) are legal.

d) The driveshaft shall be located outside of the main frame rails.

e) Two driveshaft safety loops are required. They shall be constructed so as to constrain the drive shaft in the event of a yoke or shaft failure and should be mounted 3” to 5” back from the front of the driveshaft and 3” to 5” forward from the rear of the driveshaft.

f) A restraint device shall be fastened between the torque arm (if used) and the frame so as to constrain torque arm motion and prevent injury to the driver in the event of a failure of any part on the moveable end of the torque arm.

There shall be only one engine in a SuperModified. It shall be an American made, cast iron, Chevrolet V-8 big block (including truck blocks) with 2 valves per cylinder and one spark plug per cylinder.

• No small block engine cars will be placed in competition in an ISMA/MSS event.

• Since there are no Ford or Chrysler engines a recommendation was made that Oswego remove from their rules the allowance of Ford and Chrysler big block engines to help contain options and costs for race teams.

• Would grandfather the past running 481’s. No new 481’s.

• The engine shall not exceed 470 cubic inches of displacement.

• A +1% tolerance will be allowed on the 470 cubic inch limit. This should not be considered a build limit, it is to be considered a wear tolerance to allow teams to maximize use of existing equipment.

• All engines shall use approved cylinder heads in competition.

• All cast iron heads are approved.

• Aluminum heads shall be a standard engine manufactures type (Chevrolet round port, D port, C port, and big block bow tie, Dart or Brodix) with valve angle location, placement, and standard intake port configuration.

• The intake valve angle must be from 26-23°. The magneto (or similar non-cylinder head surface) will be used as a reference for the cylinder block deck angle.

• Manufacturer’s identification number shall remain on the cylinder head.

• Any cylinder head not listed above must be approved by a tech inspector before being used in competition.

• All cylinder heads shall have standard valve angle, location, placement, and port configuration. No welding is permitted to raise the head runners, ports or manifolds which would allow or result in port relocation. The configuration of the intake port must conform with a Mr. Gasket 121 and must fit the intake port/intake bolt pattern and shape.

• The pistons shall be made of aluminum.

• The crankshaft and connecting rods shall be made of steel.

• An inspection hole on the bottom left of the oil pan shall be provided and must be of adequate diameter for inspection purposes. If the inspection hole is not provided the car owner will be required to remove the pan if inspection is requested by the tech inspectors.

• M.S.D. electronic ignition will be allowed.

• A one-year penalty is imposed for the owner, driver and crew chief if traction control or data acquisition devices are found on the race car.

• Timed injection or injection systems identified as such shall not be allowed. Electronic fuel injection systems shall not be allowed.

• Only one injector nozzle and one injector line per cylinder.

• Fuel shall be injected through the injector stack or injection manifold, not through the cylinder head.

• The fuel injection unit shall have one butterfly per cylinder.

• Adapter plates or spacers between the injection manifold and heads are not allowed.

• Three-piece injection is allowed.

• Turbochargers, superchargers, nitrous oxide and oxygen injection set ups shall not be allowed.

UNDERBODY / BELLY PANS -- All cars shall be equipped with a belly pan.

1. The underbody / belly pan must be fastened securely to the bottom of the frame rails and shall not be positioned above the frame rails to gain aerodynamic advantage.

2. The entire underbody / belly pan must extend from the left side lower frame rail to the right side lower frame rail and from the front frame rail or cross member (diagonals) closest to the front axle to the rear roll hoop with no openings or interruptions. The maximum width of the underbody / belly pan is 22.0 inches. If the outside edge of the lower frame rails is less than 22 inches the underbody / belly pan may extend beyond the frame rails to a maximum of 22.0 inches with the 22-inch width centered with the main frame rails. Frames designed with a taper in the planform view (top view-front to rear) will use the center of the frame rails in the tapered sections to establish the centerline for the underbody / belly pan measurement. At all points along its length, the centerline of the underbody / belly pan and the centerline of the frame must coincide.

3. Any surface which extends forward of the front main frame must be flat, in the same plane as the underbody / belly pan, and not exceed the 22-inch width of the underbody / belly pan.

4. If the underbody / belly pan extends forward of the main frame the extended portion must be less than 3 inches in length unless it provides a continuous surface to the nose cone and must be the same width and shape as the nose cone.

5. Any surface which is rearward of the rear roll hoop but is forward of rear axle centerline must not exceed the underbody / belly pan width and must be aligned with the underbody / belly pan. Any surface which is rearward of the axle centerline must not exceed the underbody / belly pan width and must terminate 6 inches forward of the outermost portion of rear bumper.

6. Vertical panels extending below underbody / belly pan anywhere between the outermost portion of front bumper to 6 inches forward of the outermost portion of rear bumper are prohibited. No skirting, channeling, tunneling or redirecting of air.

7. Flaring the bottom of the vertical panels between the upper and lower frame rails to meet the underbody / belly pan is acceptable. Vertical panels meeting with the underbody /belly pan will not extend beyond the 22-inch maximum width.

8. Fuel cells mounted above or within the main frame rails, and any panels, extensions and other surfaces facing the ground must conform to all of the above underbody /belly pan rules.

9. Rub strips made to prevent contact of the frame with race surface are allowed to extend below the frame rail by not more than 3/8 inch. Rub strips designed with the intent to channel air are prohibited.

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