4500 Modified Class

4.1 FRAME & BODY

4.1.1

The frame is considered to be the primary frame rails used to mount the drive train and body. It shall run from the OEM motor mount location to behind the rearmost portion of the occupants' seats. The balance of the frame shall remain whole however allowances will be made for suspension mounting.

4.1.2

The stock frame should be retained, however aftermarket and custom frames are allowed. Aftermarket and custom frames must be of a boxed design with minimum dimensions of 1.5” (38mm) x 3” (75mm) x 0.120” (3.0mm).

4.1.3

At static ride height the bottom of the frame rails shall be no higher than the top of the tire.

4.1.4

At no point shall the frame rails be closer than 16” (406mm), measured horizontally.

4.1.5

The frame rails must remain within 4” (100mm) of vertical alignment in relation to each other for the entire length of the frame.

4.1.6

The body is considered to be the exterior of the cab, bed, doors, hood, front/rear fenders, grill, etc.

4.1.7

All vehicles shall resemble an OEM production vehicle, and the body shall be complete with the following limitations and exceptions: Modifications to the body for performance and/or clearance are permitted but must preserve the look of the stock body, as originally manufactured.

4.1.8

For the purpose of the Modified Class; a Production Vehicle is defined as any vehicle that has a minimum of 250 chassis/body combinations sold to the public with 2 full size seats side by side.

4.2 ENGINE

4.2.1

Any and all engines are permitted, providing they meet all the additional rules and regulations specified herein, and with the following limitations and exceptions: The back of the engine-block must be located in front of the furthest-forward portion of the driver's seat, unless otherwise-equipped, as originally manufactured in a 4WD configuration.

4.2.2

Radiator mounting open

4.3 TRANSMISSION

4.3.1

Any and all transmissions are permitted, providing they meet all the additional rules and regulations specified herein.

4.4 TRANSFER-CASE

4.4.1

Any and all transfer-cases are permitted, providing they meet all the additional rules and regulations specified herein.

4.5 DRIVESHAFTS

4.5.1

Any and all driveshafts are permitted, providing they meet all the additional rules and regulations specified herein.

4.6 AXLES

4.6.1

Any and all axle assemblies are permitted, providing they meet all the additional rules and regulations specified herein.

4.7 STEERING

4.7.1

All vehicles must retain some type of mechanical steering linkage (e. g. 'full-hydro' steering is not permitted, unless factory-equipped matching frame), and said linkage must be capable of controlling the direction of the steering wheels/tires without the benefit of any additional power-steering aids. Post race inspection includes disconnection of assist system and steering must move substantially through mechanical connection alone while vehicle is stationary. Rear-steer is not permitted.

4.8 SUSPENSION

4.8.1

Any and all suspension components and configurations are permitted, providing they meet all the additional rules and regulations specified herein.

4.8.2

Shock absorbers of any make/model/type are permitted and may be installed in any location and orientation, with the following limitations and exceptions:

1. Only two shock absorbers are permitted per wheel/tire (not including spare tires).
2. Shock absorbers shall not be larger than 2.65" (67mm) in diameter (outer diameter of shock-body) and shall not be capable of any more than 14" (355.6mm) stroke.
3. Shock absorbers must be connected directly to the axle assembly and chassis and shall not be mounted in any way so as to yield any type of mechanical advantage, unless factory-equipped (mounting shock absorbers off-vertical is permitted and shall not be considered a mechanical advantage), or equipped with any type of independent suspension (and then shock absorbers may only be mounted to as to yield a mechanical advantage at the wheels/tires that are independently suspended).

4.8.3

Manual suspension controls (e.g., forced hydraulics) are not permitted.

4.8.4

Independent Suspensions are not allowed in the Modified class with the following exception:

1. Independent Suspended vehicles must use OEM Factory Frame and OEM Factory Body Style for that make/model year and the vehicle must have been Independent for that make/model year.
2. Frame requirements will exceed class rules to include suspension mounting points for the independent portion of the suspension.

4.9 WHEELS & TIRES

4.9.1

The intent of the tire rule for the modified class is to restrict tire use to only standard production models designed, sold, and advertised for use on highway vehicles. Therefore, all tires used in competition shall be readily available to the public from any local distributor. Tires with special construction, compounds, etc. created for the sole purpose of competition will not be allowed.

4.9.2

Tires must be DOT-approved, with a maximum outside diameter of 37" (or equivalent), as specified on the tire’s sidewall by the original manufacturer.