Altered Stock Four Wheel Drive is an entry level four-wheel drive truck class. Strict engine limitations powered by gasoline, keep the power levels around 600hp. They are a steel bodied vehicle with a factory driveline, turning D.O.T. approved tires.
These rules provide a good platform for a newcomer to the sport to join in the competition without a large financial investment.
Altered Stock 4WD Rules
1. Hitch height to be a maximum of 26" at hook point.
2. Drawbar length is a min. 36% of the wheelbase. Drawbar must not extend more than 12" past the
rear of the truck and must be rigid in all direction.
3. Trucks where the drawbar height adjustment link is attached to the rear differential housing, the
attaching point must be at axle centerline or below
Clutches and Flywheels
1. Steel bell housings or scatter blankets are required.
2. The flywheel, clutch and pressure plate components must be SFI approved and numbered
3. All bell housings must be flush on the inside surface.
4. SFI certified bell housing with Crower stand adjustment slot are acceptable.
5. Add two additional bolts to fasten the bell housing to block saver plate, evenly spaced on the lower
half of the bell housing. These bolts are to be 3/8-inch grade 5.
1. There is a maximum cubic inch limit of 485 cubic inches
-May run up to 540 CID, but must run OEM factory heads block and intake. ( No Bow Tie or SVO blocks)
2. No Aftermarket Engine Blocks- Must be OEM-no Tall Deck Blocks
3. Aftermarket cast iron cylinder heads are allowed. No aluminum heads.
4. No Dry Sump oil systems
5. No Vacuum Pumps
6. No Intake Runner Spacers
7. An external oil pump is allowed-one stage only
8. The spec aluminum intake is Edelbrock's Performer RPM, not the Airgap.
The GM part numbers are 7161 and 7163.
The Ford part number is 7166. And 2966
The Dodge part number is 7193.
9. The intake is not allowed to be modified in any way, with the exception of a 3/4 inch gasket
matching of port to cylinder head
10. There is no use of extrude hone or acid porting
11. No epoxy filler in intake
12. No porting around the carb mounting
13. All carburators must be 4150 based no Dominator Carburators allowed
14. An OEM intake will be allowed and cast iron manifold can be ported
15. Any size carb spacer is allowed
16. The carb will be pulled and intake inspected with a scope at the time the engine is pumped for
cubic inches. Any issues with porting by tech officials will result in pulling the intake off to measure and
17. Engine placement is stock location with min 15 inches from back of block to center of front axel
1. Truck must have factory frames and complete bodies (bed may be gutted with no weight penalty)
2. Truck must have all body components: fenders, hood, doors, bed. All original sheet metal in cab must
be intact. Tilt front ends allowed. No fiberglass bodies and no flatbeds.
3. Truck must have safety glass or Plexiglas in windshield and rear window
4. Weight box maximum width 84", not to exceed 60" forward from top center position of front axle
5. Truck must have a factory front suspension in place. Traction bars allowed. Solid suspension is
allowed in the rear.
6. Production (OEM) driveline up to 1 ton with a 133" wheelbase maximum. Dana 70 front and Dana 80
rear axle maximum.
7. The outside edge of front or rear tires must track within centerline of one another.
1. Exhaust system must run down and back or up through the hood. Adequate clearance around
headers will be allowed to permit opening of the hood.
Fuel and Fuel Containers
1. Gasoline only as fuel. No additives are allowed in gasoline except those additives blended by the fuel
manufacturer or refinery
2. Fuel cells only, no factory tanks allowed.
3. No fuel cells in driver’s compartment
1. Kill switch with a 2" diameter ring required. It must break power to the ignition and electric fuel
pump. The switch must be located approx. 12" above hitch.
2. The kill switch must be
2.Track officials and/or tech inspectors have the option of checking kill switches as they feel is adequate
at any event. It is recommended that all kill switches be check on all competing vehicles at every event.
1. Engine must be shielded at least .060" thickness. Height to extend to bottom of cylinder head and
must cover the entire length of the engine. No unnecessary holes in the firewall. Any engine driven fan
must be shrouded 360 degrees.
2. Reverse light required at the rear of the vehicle and inside the cab.
3. All driveline U-joints are to be enclosed 360 degrees using 1/4" steel or 5/16" aluminum and must be
a minimum of 6" wide with a maximum of 2" clearance from the U-joint.
4. All drive shafts between the transmission and transfer case must be completely enclosed with ¼”
steel or 5/16” aluminum and fastened securely.
5. All drive shafts must also have 3 loops 1/4" thick steel x 3/4" wide minimum.
6. If an Illiana Pullers Association track official or tech official feel a vehicle is unsafe, they have the right
not to allow vehicle to pull. Track official or tech official has the right to bar a competition vehicle from
competing if he or she believes that the vehicle has a potential safety problem.
7. All pulling vehicles must be equipped with a minimum of 2 lb Halon type of 2½ lb dry- powder type
fire extinguisher, full charged with a gauge, in working condition and convenient to the operator.
8. All trucks equipped with a harmonic balancer shall be SFI approved or shrouded with ¼” steel shield
1” wide and 360 degrees around the balancer and have two ¼” x 1” straps to keep the balancer from
9. Altered Stock competitors are required to wear a Snell 2000 helmet and a 3.2 rated single layer fire
jacket during competition.
1. 33 X 12.50 tire by Measure- no cuts, no extra sipes
2. Tires must be DOT stamped, max size 33 X 12.50r X 16.5 or 305 X 70r16
Maximum weight for truck and driver is 6200 lbs.
A $100 protest fee for intake violations by a competitor in class to pull intake off and inspect by tech
offcials and one board member will be present
All general rules apply where applicable. Rules are were locked on November 12th , 2017 for three years.