Modified Rules

2013 Modified Rules

We are unsanctioned but follow UMP rules with a revision to the tire rule. The only tires allowed are Hoosier A40′s.   Visit for any questions.  Below is a copy of the rules:

15.1 – Engine

A.) Any American made engine will be permitted as long as the rear of the engine bell
housing flange is mounted at least 72”-inches forward from the center of the rear axle.
The engine offset must remain within two (2”) inches of the center line from the cross
member. The minimum engine height when measured from the ground to the center of
the crankshaft is 11” inches.

B.) All engines used in competition must be able to be used in a conventional
passenger car without alteration. Alteration of motor mounts will not be permitted.
Alteration of the castings and/or fittings will not be permitted. Any machine work on the
outside of the engine or machine work on the front or rear of the crankshaft will not be

C.) Aluminum blocks will not be permitted.

D.) Magnetos will not be permitted.

E.) Wet sump oiling systems must be operative and will go with a claim by DIRTcar
officials. Overall dry sump systems will not be permitted.

F.) Alteration to the cooling system will be permitted. If alterations to the cooling system
are made the stock-appearing hood line must be maintained.

G.) The battery must be securely mounted and shielded. The battery must not be
mounted inside the driver’s cockpit.

H.) The exhaust system(s) must be mounted with the exhaust directed away from the
vehicle and/or away from the ground (preferably horizontal and outside the body of the
car). A maximum of 1/2” inch clearance surrounding the header pipe when directed
through the firewall on the driver’s side. Local track rules will prevail when decibel
and/or muffler rules.

I.) One two or four barrel carburetor is required.

J.) The engine must be a normally aspirated configuration.

K.) Fuel injection systems or electric fuel pumps will not be permitted.

L.) There may be specific engine rules issued for each region of North America that
deviate from the standard UMP Modified Engine rules included herein.

15.2 – Transmission & Driveline

A.) The drive shaft must be made from magnetic steel. The driveshaft must be painted
white with the car number clearly labeled on the drive shaft.

B.) Aluminum, fiberglass, or carbon fiber drive shafts will not be permitted.

C.) A 1/2”-ince x 2”-inch 18-gauge steel drive shaft hoop is mandatory. The drive shaft
hoop must be at least six (6”) inches behind the universal-joint. Two hoops are strongly

D.) All competitors are encouraged to perform systematic checks on their drive-train.

E.) Direct drives and/or any type devices will not be permitted.

F.) The transmission must be bolted to the engine. All cars must have forward and
working reverse gears and be able to shift to forward or reverse with engine running.
BERT-type transmissions will be permitted.

G.) Clutch-type transmissions must be equipped with explosion-proof steel bell
housing. In lieu of an explosion-proof bell housing or if one is not available for your
engine, a shield of at least 1/2”-inch x 6”-inches covering the clutch area 360 degrees
securely fastened in place and fabricated from magnetic steel will be permitted.

H.) The steering box must be O.E.M. Any-type rack and pinion style steering will not be
permitted. The original bolt pattern that matches frame type must be used. In the
cockpit, steering may be modified to suit the driver but must remain on the left side of
the vehicle. Moving the steering mechanisms to the center of the vehicle will not be

15.3 – Chassis/Frame

A.) Only factory production full 1950 or newer parallel American passenger car frames
will be permitted. The frame must be complete in front of firewall. Cutting of the frame in
any way in front of firewall will not be permitted.

B.) The frame must remain unaltered and must meet the requirements of the attached

C.) The Right side frame rail may not be altered and/or raised and/or moved from the
stock OEM location in any manner and must measure a maximum of six (6) inches from
the ground to the bottom or lowest edge of the frame rail.

D.) The front cross member may be notched to allow clearance for the radiator only.
The cross members must be plated to retain complete box configuration.

E.) Jeep, Bronco, 4-wheel drive, front wheel drive or sports car frames will not be

F.) The minimum wheelbase permitted will be 108” inches. The maximum wheelbase
permitted will be 112” inches.

G.) The rear of the frame may be altered to accept leaf or coil springs. Any coil spring
must be a minimum of 4-1/2” diameter.

H.) Fiberglass lift bars and/or rear torsion bars will not be permitted.

I.) Any frame may not be widened or narrowed and must be able to support the roll
cage on both sides and must be full and complete on both sides.

J.) The minimum frame and body height from ground is four (4) inches.

K.) The front bumper must be mounted to the ends of the frame with the bottom loop
parallel to the ground.

L.) A minimum of 1” diameter tubing and/or pipe is required to for towing of the vehicle.

M.) The rear bumpers must be constructed of tubing and/or flat stock. The rear bumpers
must protect the fuel cell.

N.) The bumper(s) (front and rear) when measure from their center(s) must have a
minimum of 25” inches of ground clearance. There will be a two (2) inch tolerance, plus
or minus regarding this dimension. The rear bumper and/or the nerf bars must not
extend beyond the width of rear tires. All bumpers must have round edges. Sharp
edges on any bumper and/or bumper surface will not be permitted.

O.) The brace bars forward of the roll cage must not extend higher than stock hood

P.) The rear push bars must not extend beyond six (6”) inches of the rear quarter panel
Q.) All side bars and bumpers must be capped on ends.

R.) The maximum overall width of the car, front and/or rear, shall not exceed 78” inches
when measured from the outside of the tire tread on both sides of the vehicle. A
maximum one (1”) inch spacer between the hub and wheel will be permitted. Steel
and/or aluminum spacers will be permitted, provided the overall width of the vehicle
does not exceed 78”-inches.

15.4 – Weight

A.) All added weight(s) must be painted white with the car number clearly labeled on
each weight.

B.) All added weight(s) must be securely mounted to car with minimum of two (2) 1/2”-
inch bolts that pass completely through each weight and the car. Weights that are
mounted on the rear bumper or outside the body of the car will not be permitted. All
added weight must be mounted below all windows and the interior sheet metal.

D.) The minimum weight of car with driver at all times including after the race is 2,400

E.) All weight determinations will be measured on the scales selected by the local track
officials and/or by DIRTcar Officials for each racing event. There will be no weight
tolerance after the completion of any racing event.

15.5 – Fuel Cells and Fuel

A.) All cars must have fuel cells. The maximum capacity for the fuel cell will be 32
gallons. The fuel cell must be completely enclosed in an 18-gauge magnetic steel
container. Aluminum fuel cell containers will not be permitted. All fuel cells must be
completely visible. All fuel cells must have a minimum of 2”x2” inch x 1/8”-inch steel
straps surrounding them. The fuel cell must be protected in the rear of axle by securely-
mounted (welded) roll cage tubing

C.) Any driver must be prepared to drain fuel upon request for measurement of the fuel

D.) The fuel cell must not extend lower than protective tubing.

E.) Racing gasoline or alcohol will be permitted.

F.) Nitrous oxide, nitrous methane, propylene oxide or any type of additives will not be

G.) Fuel may be inspected at any time during any event.

H.) All fuel cells must have check valve in breather and filler check valve.

15.6 – Body – (See drawing diagram for reference – There may be dimensions
referenced in the drawing diagram that are not referenced in written rules and vice
versa. All dimensions whether written and/or referenced in the drawing diagram
dimensional are rule(s),)

A.) All bodies must follow dimension(s) and the appearance as shown in diagram. The
body shall be the fabricated modified body from approved vendors.

B.) The front windshield and rear window support must be stock appearing. The front
window support(s) may have a clear Lexan support of no more than 16” inches
including the roof post at the bottom and going straight to the roof. The support must be
securely fastened in a positive manner.

C.) The front roof post must be in a straight line from top to bottom.

D.) The sides of the engine compartment will remain open. Any side panels in the
engine compartment area will not be permitted. A five (5”) inch drop on either side of
the hood will be permitted and it must enclosed at the rear of the hood. The firewall on
driver’s side must meet the front of the door.

E.) The top of the doors must remain in line with the rear engine plate. The bottom of
the doors may extend a maximum of eight (8”) inches past the motor plate toward the
front of the vehicle. Any material that exceeds 8”-inches will not be permitted.

F.) A maximum one (1”) inch flange for the purpose of strengthening only will be
permitted on the front nose only. Side fins and/or flanges of any kind along the length of
the entire car (hood, front,and/or roof) will not be permitted.

G.) The bodies should extend no further forward than the back of the block.

H.) A maximum of one (1) stone deflector, for rear mounted oil pumps, oil filters, and
for the main oil tank will be permitted. The deflector may be made of steel, aluminum, or
heavy gauge wire. The cover may only be mounted near the unit it is designed to
protect with a maximum size of eighteen (18”x18”) inches square and mounted only
from the upper right frame rail to the lower right frame rail.

I.) The minimum roof height is 42” inches with a maximum height of 52” inches.

J.) The minimum deck height is 28” inches with a maximum height of 38” inches.

K.) All cars must have a car number on both sides and the roof that are at least 18”
inches in height and 14” inches in width.

L.) The driver’s last name must be displayed under the car number in a legible font that
is a minimum of eight (8”) inch high letters.

M.) A/ a minimum of two (2”) inches of tire clearance from the body is required.

N.) The minimum ground clearance will be four (4”) inches.

O.) The measurement from center of the hub to the rear top of deck will be a minimum
of 34” inches and a maximum of 48” inches.

P.) The maximum body width will be 72” inches at the bodies widest points. The
minimum width will be 53” inches at the bodies narrowest points. The top of the doors
may have a maximum width of 68” inches and the bottom of the doors may have a
maximum width of 72″ inches. The body width at rear wheel openings may have a
maximum width of 74″ inches.

Q.) On the left side the rear of the door may flare out six (2”) inches for tire clearance.

R.) The bottom of the flare must be curved and rounded not pointed in any fashion.

S.) The maximum rear width of car must be 67” inches at the widest point.

T.) The maximum roof width will be 50” inches with a minimum of 44” inches.

U.) The maximum roof length will be 56” inches with a minimum roof length of 41”

V.) The maximum height on rear roof post vertical is 5” inches.

W.) The nose piece shall not be longer than frame horns and shall not attached any
further back than the radiator. The nose piece must not exceed 45”-inches in width,
centered between the frame rails and must not extend past the leading edge of the front
bumper. The nose piece must have a minimum of six (6”) inches from the ground to the
bottom edge of the nose piece.

X.) The spoiler shall be a maximum of 5” inches tall. Any spoiler angle will be permitted.
Three (3) spoiler supports may be used; this includes side spoilers. The spoiler
supports and side spoilers shall be 5” inches tall in the back and 2” inches tall in the
front with a maximum total length of 12” inches at the bottom.

Y.) The spoiler may be fabricated from lexan or aluminum. You may use the roof
post/spoiler kit. The kit has the roof post and spoiler fabricated in one piece. If the kit is
utilized the spoiler height must remain 5” inches.

15.6.1 – Interior and Driver Compartment

A.) All windows must have a minimum 11”-inch vertical opening. The entire interior must
have a minimum of 11”-inches of clearance from the interior deck to the roof and all
sections of the roll cage. The minimum window opening will be 12”inches. The interior
deck sheet metal to the right side of the driver from the back of the seat forward should
be fabricated on an angle from the driveshaft tunnel to the right side window to promote
ease of exit for the driver through the right side and or front window opening.

B.) A master ignition switch within easy reach of the driver is mandatory. The switch
must be clearly labeled “ON” and “OFF”.

C.) Hydraulic and/or pneumatic weight jacks, trackers, or similar adjustable
components of any type will not be permitted.

D.) Mirrors of any type will not be permitted.

E.) The rock guard should end at a point perpendicular to the steering wheel.

F.) The drivers compartment must be sealed from the engine and the race track. The
rear bubble of the hood should be closed and sealed from the driver.

G.) The maximum slope/rake of the interior sheet metal “shelf” front-to-rear is 4”-inches
when measured from the firewall to the base of the spoiler. A maximum of 2”-inches of
slope/rake will be permitted in front of the rear of the seat to the firewall and a maximum
of 2”-inches of slope/rake will be permitted from the rear of the seat to the base of the
spoiler. The interior sheet metal must remain flat and level from side-to-side.

H.) The top of the interior must be flush with the top of door and quarter panels.

15.6.2 – Roof & Roof Supports (see drawing diagram for reference)

A.) All roofs must be full size. Half-moon roofs will not be permitted. The roof may not be
mounted more than 12” (twelve inches) past the rear axle.

B.) Wings, roof spoilers or ground effects of any kind will not be permitted.

C.) All flat type roofs will be allowed a maximum 3”-inch difference in height between
the front of the roof and the rear of the roof. This measurement may be taken from the
interior and/or the ground up in any circumstance. The rear of the roof must maintain the
same height from side-to-side.

D.) All curved type roofs will be allowed a maximum of 5”-inches in the front and 2”-
inches in the rear. The break in the roof must be within 6”-inches from the center of the

E.) Wedge roofs will not be permitted.

F.) Dished roofs will not be permitted. Roofs must be rounded side-to-side. Bead rolls
will be permitted.

G.) The rear roof post must begin where it meets the back edge of the roof. The rear
roof supports may not extend past the front side of rear upright of the roll cage.

H.) The side vents on the front roof posts may extend rear ward from the lowest point, a
maximum of 16”-inches, then at a 90 degree angle to roof for one (1) configuration,
side vents must meet the outside of the car.

I. )The roof side (sail) panel window size must be a minimum of 10”-inches x 15”-inches
and must match drawing number -2- side view. A maximum crown of two (2) inches will
be permitted, measured from the center of a common tangent point on either side of
the crown.

I.) If the long roof side (sail) panel is being used there will be no radius.

J.) Any sun shield must be on hinge for easy exiting, taping will not be permitted. The
window opening must remain at a minimum of 12”-inches.

K.) All race cars must meet the measurements illustrated in the DIRTcar drawing.

L.) There are only 5 (five) approved roof supports to choose from.

M.) The roof should be single thickness of material. The roll bar hoops must be
exposed for inspection.

O.) If the roof is curved then a level will be placed on the top of the car and if the roof is
5”- inches or less in the front and 2”-inches or less in the rear and the break is in the
middle then the roof will be permitted.

P.) The roofs on these cars will be stock appearing. If a DIRTcar and/or local track
official determines the roof does not meet the requirements as stated above then a
penalty as determined by the official may be determined prior to competition, additional
weight and/or other penalties, unless the roof can be returned to within the parameter
as stated above prior to competition in the event that the roof was inspected for.

15.7 – Suspension

A.) Any “live axle”-type rear ends will not be permitted.

B.) Quick change rear ends will be permitted.

C.) Aluminum birdcages will not be permitted.

D.) Independent rear suspensions will not be permitted.

E.) Only floater hub assemblies will be permitted.

F.) The front suspension must be O.E.M. and be in stock location. The front suspension
must have replaceable stock part(s) from the same type of suspension.

G.) Aluminum spools will be permitted.

H.) Steel coil-over eliminators and/or steel/aluminum coil-over kits will be permitted.
The coil-over eliminators and/or coil-over kits must conform to the shock and spring
rules. In the rear of the car a minimum 5”-inch spring is required.

I.) All springs must have a tethered and/or cable system in place to securely fasten them
in position in the car.

J.) Aluminum shocks are ok. Aluminum shells, aluminum hubs, aluminum A-frames,
aluminum rear-end, aluminum tubes and/or other aluminum suspension parts will not be

K.) Only steel body, one piece non-adjustable shocks will be permitted. Adjustable
shocks will not be permitted.

L.) Coils over shocks of any type on the front of the car will not be permitted.

M.) Only one shock per wheel will be permitted. Lay down shocks less than 12” (twelve
inches) away from brake rotor will not be permitted. Additional shocks in other locations
will be permitted.

O.) Only stock passenger car spindles will be permitted. Fabricated spindles will not be

P.) Alterations and/or relocation of the lower A-frames will not be permitted. DIRTcar
approved after-market lower control arms, which are mounted in the OEM location will
be permitted. All after-market lower control arms must have an official DIRTcar-
approved and numbered decal displayed for ease of inspection at all times.

Q.) Tubular-type upper A-frames will be permitted. The upper A-frame mounting
locations may be altered. Aluminum cross shafts will be permitted.

R.) Composite leaf springs will be permitted.

S.) Aluminum shackles will be permitted.

15.7.1 – Brakes

A.) All cars must be equipped with a working braking system on all four wheels and all
four wheels must be able to stop/brake at all times.

B.) Only magnetic steel rotors will be permitted. Carbon fiber and/or aluminum rotors
will not be permitted. Drilling, lightening and/or any alteration to the brake rotors or
calipers will not be permitted.

C.) Only stock O.E.M. and/or DIRTcar approved aftermarket calipers will be permitted.
Only the Wilwood P/N # 120-7197 is DIRTcar approved.

(per Rule Ammendment 6/10/11)

D.) Only stock O.E.M. rotors will be permitted. Single disc brake rotors or scalloped
rotors will not be permitted.

15.8 – Wheels and Tires

A.) The tire rule may be amended by bulletin.

B.) The only approved tire is the Hoosier A-40
compound in the DIRTcar plated tire 26.5/8.0/15 or 27.5/8.0/15. The maximum width
of the tire will be 9” inches.

C.) Grooving of any tire will not be permitted. Siping will be permitted on the A-40. Recapping of an approved tire is not permitted.

D.) Any local track and/or DIRTcar official can confiscate any tire at any time and during
any DIRTcar event to be evaluated and analyzed including verification using a tire
durometer. Tires may also be submitted for further chemical analysis.

E.) Defacing or altering any of the manufacturer’s identification markings, letters,
words, numbers, on any tire will not be permitted. The tire compounds may be covered
by duct tape as long as the local track and/or DIRTcar officials are able to remove the
covering at any time for inspection purposes. Any alteration of tires may result in
immediate suspension from all DIRTcar racetracks and/or events and/or penalties
deemed appropriate by local track and/or DIRTcar and/or World Racing Group
Supervisory Officials.

F.) Tire softeners and/or chemicals designed to alter the chemical characteristics of the
tire and/or the tire surface will not be permitted.

G.) Mud plugs are will be permitted on all four wheels. Bead locks will be permitted on
the right side only. The mud plug must have the car number on it.

H.) Only 8-inch DIRTcar approved and labeled racing wheels will be permitted.

I.) All wheels must be conventional one-piece magnetic steel and must be mounted with
lug nuts. Aluminum, plastic and/or carbon fiber wheels will not be permitted.

J.) All wheels must be fastened to the hub with five lug nuts.

15.9 – Personal Protection Equipment

15.9.1. General

A.) It is the sole responsibility of each competitor for the effectiveness and proper
installation, per the manufacturer’s specifications to be adequate for competition at
every event. Each competitor is expected to investigate and educate themselves for
continuing improvement regarding their own personal safety equipment.

15.9.2 Seat Belt/Restraint System

A.) Each car should be equipped with an SFI 16.5 or SFI 16.1 approved seat belt
restraint system until the date of the belt expiration (usually two years). Seat belts
restraint systems shall be installed in accordance with the directions and application of
the system supplier or manufacturer.

B.) Seat belt webbing that comes into contact with any sharp or unradiused metal edge
should be protected from that edge by means of push on grip vinyl trim.. Seat
manufacturers supply the seat with trim protecting the webbing from abrasion or cutting
under impact conditions and should be used to their specifications.

C.) It is the responsibility of the driver, not the Officials or the Promoter to ensure that
his/her seat belt restraint system and all components are SFI approved, correctly
installed, maintained and properly used.

15.9.3 Protective Clothing

A.) Each driver should wear a fire resistant uniform meeting the SFI 3.2A/5
specification and display a valid SFI 3.2A/5 label.

B.) Each driver should also wear fire resistant accessories that effectively cover the
remaining parts of the body. Shoes and gloves should meet the SFI 3.3 specification
and display a valid SFI.3label.

15.9.4 Seats

A.) An aluminum seat built specifically for the purpose of competition in auto-racing
events will be required

B.) High-back Aluminum (stockcar style) seats should be securely mounted to the frame
as recommended/required by seat manufacturer and chassis manufacturer.

C.) Head rest (behind the head) should include padding. All areas surrounding the head
should have padding

D.) A right head net or support is required. Head nets must be equipped with quick
release mechanisms

E.) The seat must be mounted a minimum of 30” (inches) from the center of the rear
end, measured at the bottom of the seat

15.9.5 Helmets

A.) Driver should wear a full face helmet, with at least a valid SA 2000 or SA 2005
Standard Snell and/or a valid SFI 31.1, SFI 31.2 or SFI 31.1 2000 label.

B.) The driver should wear the helmet in accordance with the directions provided by the
helmet manufacturer and/or supplier.

C.) If a head and neck restraint system is connected it should conform to the
manufactures mounting instructions.

D.) Head and Neck restraints are strongly recommended.

15.9.6 Other

A.) No sharp or protruding edges in or around the cockpit, which would impede the
driver’s rapid exit from the car.

B.) Windshield screens with a minimum of .090 inch screens must be securely fastened

C.) An electrical engine shut off switch is required. The switch must be clearly labeled
and within the reach of the driver.

D.) A fuel shut off valve is required. The valve must clearly labeled and within reach of
the driver.

E.) Flame retardant seat, roll bar, knee and steering pads or padding are

15.10 – Roll Cage

A.) All cars must have a roll cage. The roll cage must be approved prior to competition
and it must be welded to the frame. The driver’s head must not protrude above the top
of the roll cage with the driver’s helmet on. The top of the roll cage must extend above
the top of the driver’s helmet by a minimum of one (1) inch. The entire roll cage and all
roll bar pieces must be fabricated from magnetic steel a minimum of .095” in thickness.

B.) The driver and right side door bars must be parallel to the ground and located
perpendicular to the driver. There must be right side door bars. The side bars must be
welded to the front and rear of the roll cage. No brazing or soldering is permitted. The
door bars must have a minimum thickness of .095” and must have a minimum of 1-1/2”
diameter. On the driver’s side there will be a minimum of three (3) door bars.

C.) Foot protection is mandatory. One piece of magnetic steel tubing, a minimum .095”
in thickness, must be fastened and/or welded across the back of the engine with
vertical tubing a minimum of .095” thick.

D.) The door side roll bars are mandatory and must extend into the door panels.

E.) The roll cage must consist of continuous hoops that are no less than 1-1/2” in
diameter and must a minimum thickness of .095”.

F.) The roll cage must be mounted securely (welded) to the frame in a minimum of 6
(six) places.

G.) The roll cage must consist of a configuration of front and rear hoops connected by
tubing on the sides and/or side hoops. Roll cage must be securely supported and
braced. Gussets to brace any portion of the roll cage will be permitted.

15.11 – Other

Section 15.11.1 – Electronic Devices & Traction Control

A.) All electronic and/or computerized wheel spin and/or acceleration retardation
traction control devices will not be permitted. Controlled timing devices attached to or
controlling accelerator or rotation of wheel will not be permitted.

B.) All traction control devices utilizing wheel sensors and/or any means of measuring
ground speed to control wheel spin will not be permitted.

C.) Adjustable ping control devices, dial a chip controls, timing controls or automated
throttle controls will not be permitted in cockpit or driver accessible areas.

D.) Adjustable restrictor plates will not be permitted.

E.) Any remotely controlled components inside or outside the cockpit of any competitor’
s racecar will not be permitted.

F.) Radios or devices for transmitting voice or data will not be permitted, either in the
racecar or on anyone connected with the car.