The rules below are the Dirtcar 2017 Rules, this will be used a guideline for the car and the engine. When 2019 Dirtcar rules are released, they will supercede these posted below. The sportsman class is DIRTCAR sanctioned for 2019.
- The 2017 Hoosier tire and wheel package for Dirtcar Sportsman will be only legal combonation. D300, 400, 500 Hoosier. LF 11/82-15 ,RF 13/82-15, LR 13/87-15 OR 13/89-15, RR 13/92-15 . Aluminum wheels are legal.
- Dirtcar mandated rev box will be required in 2017
- Only GM seal bolt or Dirtcar installed steal tags will be legal on all crate GM engines. No other seals will be legal (such as RUSH).
- All cars must maintain 2450 lbs after any event. Weight shown on track scales are final.
- No open Sportsman engines allowed.
- racing fuel or pump gas may be used.
- These rules are subject to have revisions as they are needed by the discretion of the tech team and will be given much advanced notice.
15.0-C DIRTcar Sportsman Modified
ANY CAR, TEAM AND/OR DRIVER THAT DOES NOT MEET THESE SPECIFICATIONS AND/OR
EQUIPMENT REQUIREMENTS WILL BE SUBJECT TO PENALTIES AS DETERMINED BY THE
DIRTcar and/or World Racing Group OFFICIALS.
Note; Unless otherwise noted within Section 15.0-C, the rules remain the
same as presented in section 15.0-A.
A.) The General Motors (GM) / Chevrolet Performance Engine part number #88958602/19258602
is the only engine permitted in all DIRTcar Sportsman Modified events.
B.) The engine and all components must remain in their original configuration and form as
purchased and/or delivered from the factory. Any alterations to the engine will not be permitted.
The Engine must remain as manufactured by General Motors with a stock 4”-inch bore.
Overbore(s) will not be permitted. Sleeve repair may be permitted with written permission from
DIRTcar and/or World Racing Group Officials.
C.) All engines are to remain sealed from the factory. The original factory seals must remain
unaltered, Tampering, removal, modifications of any type and/or broken factory seals will not be
permitted. The GM Engine must remain unaltered in any way.
D.) The GM Crate Engine seals (bolt-type) must remain unaltered. DIRTcar and/or World Racing
Group Officials may require specific sealing and verification of all seals on any GM Crate Engine.
Tampering with and/or alteration of any seals will not be permitted and is subject to immediate
penalty and/or suspension.
E.) Only GM replacement parts of any type will be permitted for any type of replacement and/or
repair work. Only GM Crate Engine specific valve springs may be used for replacement and/or
repair, Part Number # 10212811.
F.) GM Crate Engine repairs must be authorized by DIRTcar. GM Crate Engine repair procedure
works as follows:
1.) Contact your track promoter and/or your local track and/or DIRTcar Technical Officials.
2.) The Promoter and/or Technical Officials will specify a repair location and instruct the
driver/owner where to take the engine to get an estimate.
3.) Based on the estimate and the detail of the repair, DIRTcar and/or World Racing
Group officials will determine if the repairs may be made or if a new engine must be
4.) If a repair is approved, a specified inspector will inspect the engine and work with the
engine repair facility throughout the duration of the repair to ensure that the engine
maintains the GM Specifications.
5.) Upon completion of the repair(s) the engine will be ‘resealed’ before being released for
6.) All parts including the gasket repair kit(s) must be stock OEM Chevrolet Performance
replacement parts. The receipt(s) generated from the Chevrolet Performance Dealer
and/or parts department must be retained and a copy presented to DIRTcar for
7.) Overbores will not be permitted. If a cylinder has scoring and/or needs repair it must be
communicated to DIRTcar officials before being sleeved to maintain the original bore size.
8.) Valve jobs will not be permitted. Valves may be lapped.
9.) If the cylinder head requires resurfacing and/or valve seats, a new cylinder head must
be purchased. Machine work of any type will not be permitted to the cylinder heads.
10.) Bead blasting and/or any polishing and/or any alteration to the intake manifold and/or
cylinder heads will not be permitted.
11.) The distributor advance curve and/or all parts must remain stock as manufactured.62
12.) All engine information regarding repairs and/or engine introduction must be retained
and turned into DIRTcar Officials, to track and manage engine database, including the
driver, serial number, repair, type of repair and/or what type of service was performed to
13.) If any repair estimates come back to the DIRTcar Officials that meet and/or exceed
80% of the actual price of a new engine, a new engine must be purchased. The engine
that was damaged will no longer be eligible for competition.
G.) DIRTcar and/or World Racing Group Supervisory Officials reserve the right to technically
inspect, exchange and/or confiscate any GM Crate Engine at any time. Failure to surrender the
engine and/or submit the engine for inspection equals disqualification from the event and/or
H.) The intended direction of the GM Crate Engine program is to maintain a cost-effective,
affordable racing program. Rebuilding, balancing, blue printing and/or any other alteration made in
an attempt to influence the integrity of this program will not be permitted. The judgment and
determination of any such decision will be at the sole discretion of DIRTcar and/or World Racing
15.1.3 Carburetor / Air Cleaner
A.) Only one (1) 650 cfm Holley carburetor, Part Number 4777 or 80777 or Holley HP Carburetor
Part Number 80541-1 will be permitted.
B.) All engines and all components must remain in their original configuration and form as
purchased and/or delivered from the factory. Any changes will result in disqualification from the
event. Any alterations to the engine will not be permitted.
C.) 4777 and 80777 Option:
1.) The carburetor must maintain the stock venture and throttle bore dimensions.
2.) The carburetor must maintain all stock dimensions, including mounting and stud
location on intake manifold.
3.) The booster height must remain stock OEM from Holley. Cutting, tumbling and/or
polishing will not be permitted.
4.) Visible modifications will not be permitted.
5.) The maximum height of the carburetor when measured from the bottom of the
carburetor and/or the throttle plate to the machined horizontal surface of block will be in
7”-inches in both the front and rear of the block.
6.) The following alterations will be permitted;
a.) Holes drilled in the throttle plate for proper idle.
b.) Drilling, tapping and plugging of unused vacuum ports.
c.) Welding of throttle shaft to linkage arm.
d.) Drilling of idle and/or high speed air correction jets.
e.) Milling of center carburetor body metering block surface, maximum of .015”
on each side.
f.) Removal of choke plate and shaft.
g.) The jets may be changed as needed.
7.) Gauge measurements (go/no-go) must be met at all times, regardless of carburetor
C.) HP 80541-1 Option:
1.) The carburetor must remain stock retaining all Holley measurements and dimensions.
The carburetor may be adjusted utilizing only specified Holley replacement parts.
2.) Jets, bleeds, needle and seat, emulsion bleeds, power valves, accelerator pumps
nozzles and accelerator pump cam adjustments will be permitted.
3.) Physical alteration of carburetor components and/or parts and/or any alterations,
machining and/or reshaping will not be permitted. The use of epoxy and/or coatings of any
kind will not be permitted.63
D.) A single unaltered carburetor spacer plate with an unaltered square hole/opening including
gasket with a maximum thickness of 1-1/8”-inch will be permitted. Tapering, machining and/or any
other alteration to the spacer plate will not be permitted.
E.) Only a single conventional round type air cleaner housing will be permitted. Ram air, air box
and/or heat shield type devices will not be permitted. The air cleaner must remain in place when
the hood is removed.
F.) Air cleaners that provide ventilation through the top cover (such as the K & N brand) will be
G.) Air induction plastic carburetor insert and/or other devices that direct air into the air intake will
not be permitted.
H.) Air diffusers will not be permitted.
A.) Only stock OEM distributors will be permitted. The distributor must maintain the factory
mechanical advance curve to stock OEM specifications. Alterations and/or adjustments will not be
B.) The ignition amplifier box (“rev box”) and coil must be mounted under the hood (out of the
driver’s reach) for ease of inspection. The black wire must be grounded to the motor. When the
hood is removed the “rev box” must be clearly visible and not covered.
C.) The car must be fitted with one (1) unaltered approved MSD/DIRTcar RPM (rev) limiting box,
part number 87286 with a DIRT 6,000 RPM chip. The box and the chip must remain operable and
working condition, prior to, during and after all racing events.
C.) The “rev box” RPM limiting chip (6,000 RPM) must face up and be securely fasted (taped in) in
the “rev box”.
D.) Trigger-type and/or crank trigger-type ignitions will not be permitted.
E.) The ignition must be mechanically driven in the stock OEM location.
F.) Only the stock OEM H.E.I. ignition coil will be permitted.
G.) The wiring must remain as specified by the ignition amplifier box manufacturer.
H.) One American Passenger Car sized battery with terminals on top and a maximum of 12 volts
will be permitted. The battery voltage must not measure more than 14.3 volts. Step up transformer
and/or any other device designed to increase voltage will not be permitted.
I.) OEM stock firing order must be maintained for all engines. Standard GM Firing Order 18436572.
J.) Ignition amplifier boxes, “rev boxes”, RPM limiting chips, may be inspected, confiscated and/or
exchanged at any time.
K.) Traction control devices will not be permitted. Braking devices that control traction will not be
L.) DIRTcar and/or World Racing Group officials reserve the rights to analyze and/or switch ignition
boxes and/or rev chips at anytime.
15.1.7 Lubrication/Oiling System/Oil Cooler
A.) Only a single wet sump oil pump will be permitted. Dry sump oil systems will not be permitted.
B.) Only magnetic steel oil pans will be permitted.
C.) External type oil pumps and/or vacuum pumps will not be permitted.
D.) Accu Sumps will not be permitted.
E.) Engine evacuation systems by internal and/or external driven pumps or by connection between
exhaust system and/or valve covers, intake manifold and/or oil pan will not be permitted.
F.) Oil coolers will be permitted. Please refer to section 15.1.7-A (Big Block section) for mounting
location and other rules specific to the oil cooler.64
15.1.10 – Driveshaft
A.) Only magnetic steel drive shafts will be permitted. Titanium and/or aluminum drive shafts and/or
drive shaft yokes and/or driveline components will not be permitted.
15.1.11 – Engine Cooling System/Radiator
A.) Only cast iron water pumps will be permitted.
B.) The cooling fan for the radiator must be mounted in the stock OEM location on the front
of the water pump. Fans mounted to the crankshaft will not be permitted. Electric cooling fans
and/or pumps will not be permitted.
15.1.12 – Rear End
A.) All rear end components, ring and pinion, gear sets and/or any other component, must
be specific for the rear end in the car in size. Only full-size type rear ends will be permitted.
A minimum of 8”-inch diameter ring gear will be permitted. Miniature rear end housings will
not be permitted.
B.) Titanium axles and/or any other titanium rear end component will not be permitted.
15.2 Fuel, Fuel Cells and Fuel System
A.) Fuel coolers of any type will not be permitted.
B.) Only ‘D’-type VP Racing Gasoline, the official fuel of DIRTcar will be permitted for
competition. D-98 will be the only specified fuel permitted at any sanctioned DIRTcar
and/or Super DIRTcar Series event. In addition a maximum “94 octane, R+M/2” standard
pump gasoline will be permitted. Blending of fuels or gasoline, including VP spec
(including ‘D’) fuels of different octane will not be permitted. Alcohol, methanol, nitrous
oxide, nitro-methane and/or propylene oxide will not be permitted. Fuel may be subject to
inspection and testing at any time. Proof of purchase for the official fuel of DIRTcar may be
C.) Only one mechanical fuel pump in the stock location will be permitted. Fuel must be
delivered through the fuel system from the fuel cell to the mechanical fuel pump. Fuel
systems that require a return line, a pressure regulator of any type and/or other volume
and/or pressure altering device will not be permitted.
15.3 Exhaust – Muffler and Sound Reduction Devices
A.) Only Schoenfeld headers, model number: 1122b, 1122bcm, 4122b and 3122b will be permitted.
The exhaust headers must not exceed 1-5/8” in outside diameter. Tri-Y, step headers, stainless
steel, coated, ceramic and/or otherwise, and/or merge collectors will not be permitted.
B.) The permitted mufflers include: Dynomax part number: 17223 and 17296; Extreme Muffler part
number(s): 31530 and 31230; Beyea part number(s): MUF3DM.
C.) The header collector extension pipe and tail pipe must be inserted past the muffler inlet or outlet
flange and must exit behind the driver.
D.) All Schoenfeld headers must be able to be separated from the rest of the exhaust system
for the purpose of inspection.
E.) The complete exhaust system must be sealed. Any type of add on, return system and/or
exhaust evacuation system will not be permitted.
15.6 Weight / Ballast
A.) All DIRTcar Sportsman Modified must maintain utilizing the GM Crate Engines must maintain a
minimum weight of 2,450 lbs following the completion of any event.
B.) Any track permitting Sportsman Modifieds to compete with the previous ‘Open Motor’ package,
those cars must maintain a minimum overall weight of 2,650 lbs following the completion of any
C.) During all Mr. DIRTcar Sportsman Series events, only the GM 602 Crate Engine will be
permitted with a minimum overall weight of 2,450 lbs. “Open Motor” packages will not be permitted
to compete in Mr. DIRTcar Sportsman Series events.
A.) The letters of the driver’s last name must be a minimum of six 6”-inches in height and be
positioned under, through and/or above the number on both sides of the car.
15.7.16 Bumpers and Side Bars/Nerf Bars
E.) Rub rails may only be a single bar piece of tubing from front-to-rear for DIRTcar
Sportsman Modifieds only. Rub rails that have additional rails parallel to the main rail will
not be permitted.
15.7.14 Driver Compartment
A.) Rear panhard bar adjustment devices will not be permitted in the driver compartment. Any rear
panhard adjustments that have a knob and/or an adjustment device outside of the cockpit must be
wired in a fixed position for competition. Adjustable panhard devices of any type will not be
permitted during competition.
15.8.2 Shock Absorbers
A.) Only the DIRTcar approved –A-B-C type shock absorbers displaying the DIRTcar “Approved”
decal will be permitted to compete.
B.) Approved Shock Absorbers: All shock absorbers for the DIRTcar Sportsman Modifieds,
DIRTcar Pro Stock, DIRTcar Pro Late Model, DIRTcar UMP Sportsman and DIRTcar UMP Stock
Car division must be approved and display an approved designation decal. There will be three
types of approved designations, ‘A’, ‘B’ and ‘C’..
Approved ‘A’-type Shock Absorbers:
DIRTcar Sportsman Modified
DIRTcar Pro Stock
DIRTcar Pro Late Model
DIRTcar UMP Sportsman
DIRTcar UMP Stock Car
Pro Shocks – WB and SS Series
Bilstein – AK and SG/SM Series
AFCO – 1020-1034 Series
AFCO – 1273-1295 Series
AFCO – 1473-1497 Series
Approved ‘B’-type Shock Absorbers:
DIRTcar Sportsman Modified
DIRTcar Pro Late Model
DIRTcar Pro Stock
Pro Shocks – TA Series
Bilstein – SL/SZ Series
AFCO – 1000 Series
Approved ‘C’-type Shock Absorbers:
DIRTcar Sportsman Modified
DIRTcar Pro Late Model
AFCO – 1300 Series
AFCO – 2100 Series
Genesis – GD Series (steel body)
Integra – 310-45170 or 310-45190
Advance (ARS) – P/N ARS 2074
Advance (ARS) – P/N ARS 2092
FOX – 983-91-507
FOX – 983-91-509
Pro Shocks – PG Series
Bilstein – SL/SZ Series
Bilstein – SNS Series
Shock Absorbers must be submitted to World Racing Group for competition approval prior to the
application of the shock absorber designation decal.
15.8.6 Wheelbase and Tread Width
B.) The maximum front tread width will be 86”-inches with a minimum of 74”-inches. The maximum
rear tread width will be 86”-inches with a minimum of 74”-inches. These measurements will be
taken from the outside edge of the sidewall of the tires on each side. 66
A.) Only one-piece steel wheels will be permitted for competition. Aluminum, magnesium, steel,
carbon fiber and/or any other exotic type material will not be permitted.
C.) The maximum rim width will be 14”-inches when measured from the inside of left bead to the
inside of the right bead of the wheel. Only wheels 15”-inches in diameter will be permitted.
D.) Only beadlocks on the outside of any wheel will be permitted. Any wheel utilizing a beadlock
must maintain a minimum diameter hole of 11” or 5” inches inside the beadlock and the wheel.
Beadlocks may only be used on the outside of the wheel.
E.) Wheel covers and/or hubcaps will not be permitted on the inside of the wheel(s). Wheel covers
and/or hub caps will be permitted on the outside of the wheel providing they maintain are one
piece, positively fastened to the wheel and/or beadlock and that they maintain a minimum thickness
of .090” with a minimum 1”-inch diameter hole in the center of the cover.
F.) Foam inserts and/or corrugated plastic (with approved installation) may be permitted. If wheel
covers are not properly installed, they may not be permitted.
G.) A minimum of five (5) lug nuts on the rear wheels will be required. A minimum of three (3) lug
nuts will be required on the front wheels. Knock off hubs of any type on any wheel will not be
A.) Individual race tracks, events and/or series may designate a particular tire and/or compound at
any time. The compound may be announced prior to the event in a bulletin and/or at the driver’s
B.) Only Hoosier Racing Tires will be permitted in any DIRTcar sanctioned events. Hoosier (the tire
manufacturer) will mark/stamp/brand all legal tires with specified compound and/or other specific
DIRTcar designations as listed below;
DIRTcar Sportsman Modified:
1.) “DIRT 200” (Soft)
2.) “DIRT 300” Soft
3.) “DIRT 400” Hard
Tire Size and Compound Designation:
Fronts 11/82-15 (D 200 Soft, D 300 Soft, D 400 Hard)
Rears 11/87-15 or 11/90-15 (M 45, D 50, D 60, RC-6 X-Tra Hard)
D.) The altering of any tire compound, by any means will not be permitted. Chemical alteration of
the tread carcass and/or tread compound, such as tire ‘soaking’ and or the introduction of tread
‘softener’ and/or the physical defacement (removal, altering and/or covering) of tire sidewall
markings in any manner will not be permitted. If any competitor is found to have altered their tires
any penalty deemed appropriate by Super DIRTcar Series and/or DIRTcar Officials may be issued.
Tires may be protested by another competitor following the protest rules as stated in section 11.2.
1.) Any tire may be inspected and/or analyzed for alteration at any time. This will consist of
a process as determined by the independent laboratory that performs the analysis. A
“Chain of Custody” process will be outlined with the competitor upon inspection of the
2.) The analysis process will require shipment of the tire to the selected laboratory.
Additional race event(s) may be completed before a determination is made. If a penalty is 67
issued, the event(s) that fell into the analysis time period while the tire(s) were being
analyzed will be considered as part of the penalty time period.
3.) Reference Section 5.3.D. for Competitive Analysis, Section 11.1.I for Penalties and/or
Section 11.2.I for Protest(s).
F.) Heating of the tires by torch, blanket, heating device(s), exhaust system and/or any other
method will not be permitted.
G.) Inner liners of any type will not be permitted.
H.) A tire durometer may be used during the tire inspection process, provided baseline tire(s) have
been read at the event prior to inspection.