2008 Late Model Rules

SECTION 1: WHEELBASE

A.  The minimum average wheelbase is 103 inches.  (No tolerance.)

B.   Rear suspension is optional, but no devices allowed of any kind that are designed to change the wheelbase of the car while in competition will be permitted.  (Control arms with springs or rubber bushings not permitted on the rear of the car.)  Limiting devices will be allowed on the left rear only.

SECTION 2: ENGINES

I. General Engine Rules

       A. Engines may be interchanged within manufacturer lines.

       B. The Chevrolet Vortec and SB2 engine will not be permitted.

       C. Any eligible cast iron O.E.M. cylinder block permitted.

       D. Aluminum blocks will be permitted, but must have a minimum of 75 pounds bolted to the frame of the car ahead of the rear of the engine

       E. The engine block must retain all standard external dimensions with the exception of the maximum allowable overbore and the surfacing of the block deck.  Angle cutting of the block deck will not be permitted.

       F. Car weights may be changed at any time at the discretion of the officials.

II.Engine Set-Backs

       A. All competing models using an engine larger than G.M. 361 cubic inches or Ford or Chrysler larger than 364 cubic inches are allowed a maximum engine set back of 6 inches ( to be measured from the center of the forward most spark plug hole to the center of the upper ball joint.)

       B. All competing models using a Ford or Chrysler engine 364 cubic inches or smaller or a G.M. engine 361 cubic inches or smaller are allowed a maximum engine set back of 8 inches.

III. Steel Head Engine Rules (Small Cubic Inch)

       A. Only O.E.M. stock production steel heads as numbered below will be allowed.

       B. No Dart, Vortec, fuel injected, Ford Cleveland, or GT40.

       C. Heads will be G.M. bowtie cylinder head part number 10134392, 14011058, or 12480034 casting number 14011034, Ford M-6049-n351, Mopar head casting number 4532693.  Mopar may run Chrysler R block #P4532907 or P4532908. Mopar heads may be 15 or 18 degrees.  O.E.M. J Design Mopar heads are not legal. No modification outside of the combustion chambers, except surfacing, three angle valve jobs, and touching up the combustion chamber.   Titanium valves and retainers, and shaft rockers will be allowed.

       D. Roller camshaft, lifters, and rocker arms will be allowed. Shaft rockers will be allowed.

       E. Any aluminum intake may be used with a maximum total height of 6” from top of intake to floor of plenum.  Up to a 2”spacer may be included in the 6” height.  No super high rise intakes allowed.  Plenum must have flat floor.

       F. May run up to and including the Holley 4150 series 850 c.f.m. carburetor.

       G. No titanium engine parts, except titanium valves and retainers.

       H. All engine casting numbers stamped on the engine will be left on the block at the bellhousing area.

       I. No epoxying of block numbers will be allowed.  Block numbers will be stamped by inspector if needed

       J. Minimum weight will be 2300 pounds after all races (this is for all engines of all makes with a compression ratio no greater than 11 to 1)

IV. Cars using heads listed above in section III-C with a compression ratio of greater than 11.0-1, must weigh a minimum of 2375 pounds.

V. Aluminum Head Engines - Engines utilizing aluminum heads with cylinder head valve angle within plus or minus 2

degrees of standard original equipment cylinder head must weigh a minimum of 2375 pounds and must utilize a 390 C.F.M. carburetor. 

VI. Engines utilizing aluminum or steel heads with cylinder head valve angle that is not within 2 degrees of standard original equipment cylinder head must weigh a minimum of 2425 pounds and must utilize a 390 C.F.M. carburetor. 

VII. Big Cubic Inch Engines – Engines with larger cubic inches than listed in Section 2, Part III must use a 390 C.F.M. carburetor and weigh a minimum of 2575 pounds.  

VIII. IMCA Spec. Motor – Engine must meet all IMCA Spec. Engine rules.   Must weigh a minimum of 2300 pounds. 

IX. If a car uses any aluminum heads, 40 pounds of total car weight (20 pounds on each side of engine) must be located between front shock mount and rear spark plug, on the tubing that the front upper shock mounts to.  Except for Crate engine option. 

X.  Crate Engine Option.  Any I-80 Speedway 602 or 604 Crate engine may compete using I-80 Speedway Crate Engine rules, with the exception of a minimum weight of 2250 pounds for both 602 and 604 engines.

SECTION 3:  FUEL AND FUEL CELL

A. Gasoline can be Sunoco 110 (purple) or 112 (blue) octane only.  (No alcohol, ethanol, or oxygen bearing additives allowed.)  

B. Commercially manufactured fuel cells mandatory, fuel cell capacity may be from 5 to 32 gallon cell, including fill spout.

C. Fuel cell cannot extend below rear end tubes.

D. All fuel cells must be encased in a metal container.

E. All fuel cells must be mounted securely to the frame of the car, and must be mounted in framework similar to diagram on reverse side of rule sheet.

F.  Fuel cells must have non-vented caps, rollover valves in return and vent lines and must pickup from top of cell.

G. All cars must be equipped with a fuel cell guard that is mounted separate of the fuel cell and is mounted securely to the frame of the car.

H. Fuel cell guard must be made of at least 1-inch tubing and must extend to the bottom of the fuel cell.

I. No electric fuel pumps allowed.  (Belt driven fuel pumps or mechanical pumps will be permitted.)

SECTION 4:  WINDSHIELD SCREENS ROLL CAGES, FRAMES

A.   All cars are required to have a screen in front of the driver, with a frame and at least 4 vertical bars in the frame besides the sidebars.  Screen must have openings no smaller than ½” X ½” and no larger than 2”X 2”.

B.   All cars are required to use a roll cage with at least 3 horizontal bars across the driver’s door.

C.   All competing models will be required to have a vent window bar and a bar in the center of the roll cage over the driver’s head.

D.   All cars will be required to have a bar to protect the driver’s feet.

SECTION 5:  CARBURETORS AND AIR CLEANERS

A. Any eligible carburetor may be used.  Approval of carburetor means approval for all competitors within the same guidelines.

B. All competing models must run the Holley 4150 series carburetor. Must meet the Holley 4150 height specs. (See Engine Rules for specific C.F.M.).

C. Any eligible dry element round air cleaner will be permitted. (Minimum 12 inches, maximum 17 inches in diameter. Maximum 4 inches in height.)

D. Only round metal air filter housing will be permitted.  The top and bottom of the air filter housing must be solid and must be the same diameter.  A maximum of a one (1) inch lip will be permitted from the air filter element to the edge of the air filter-housing top and bottom.  The air filter housing must be centered and set level on the carburetor.  It is permissible to attach a shield to the air filter housing.  The shield can be no higher than the height of the air filter element.  Tubes, funnels, or any device, which may control the flow of air, will not be permitted inside of the air cleaner or between the air filter housing and the carburetor

E. Cowl induction may be used as long as the air box is designed to draw air from under the hood.  (One side or end of air box must be open) (Hood scoops will be permitted to be open in the rear only.)

F. No carburetor air dams or devices allowed increasing the airflow to the carburetor, either inside or outside of air cleaner.

SECTION 6: CYLINDER, HEADS, INTAKE MANIFOLDS, SPACER PLATES, AND IGNITION SYSTEMS

A.  Any eligible cylinder head may be used.  Approval of cylinder heads means approval for all competitors within the same guidelines.

B. The valve centers must remain the same as production manufactured steel cylinder heads for the make and model of engine being used.

C. Intake manifold must be of stock configuration of O.E.M. manifold. (Inside of the bottom of intake manifold must be flat.  No devices permitted inside of intake manifold to disrupt the air flow to the engine.)

D. Any aluminum intake may be used with a maximum total height of 6” from top of intake to floor of plenum.  Up to a 2” spacer may be included in the 6” height.  No super high rise intakes allowed.  Plenum must have flat floor. 

E. A spacer plate may be used between the carburetor and the intake.  May be a one hole or 4-hole spacer plate, with nothing inside of the spacer plate to enhance or increase the airflow to the engine.

F. Ignition systems must be approved.  HEI and MSD ignition systems only and must be connected to a 8000 RPM rev limiting chip or module. No crank triggered ignitions. The following MSD #’s are allowed: P/N 8728, MSD Soft Touch Rev Control, is designed to be used on standard points ignition or inductive ignition systems. This means that the PN8728 can be installed on engines with a GM HEI Ignition, Ford or Chrysler electronic ignition and any standard breaker points system without an MSD box. P/N 8738 MSD Soft Touch Rev Control for use with MSD 6T, 6TN Ignition Boxes. P/N 6420 MSD 6AL Ignition Control Box with Rev Limiter Built-In. P/N 6430, MSD 6 ALN Ignition Control Box with Rev Limiter Built-In. MSD boxes must be out of reach of driver and accessible for tech.

G.  Any infraction of ignition system rules, including but not limited to  RPM limiting or traction control devices, will result in a joint penalty phase enforced at ACS and NRP.  First offense will be a $1000 fine and a 30 day suspension from NASCAR point races at both tracks.  The second offense will be a $5000 fine and a 1calendar year suspension from NASCAR point races at both tracks.  Infractions within 30 days of the end of the season that incur a 30 day penalty will result in any remainder of the suspension period being carried over to the beginning NASCAR point races of the next season at both tracks.

H. No onboard computers, micro-controllers, processors, automated electronics, recording devices, electronic memory devices, memory chips, or digital readout gages of any kind permitted. Digital Tachometers will be allowed.

I. Only one (1) electronic firing module amplifier is permitted, if used.

J. Only one ignition coil permitted.

SECTION 7:  CLUTCH, FLYWHEEL AND BELL-HOUSING

A. High speed multiple disc clutches are permitted.

B. All cars must be able to be put in and out of gear with the engine running and the car sitting still.

C. All competing models must be equipped with a flywheel and an operable starter.

D. A production manufactured steel bell housing or a heavy duty explosion proof aluminum bell housing may be used on all models.  

SECTION 8:  TRANSMISSION, DRIVE-SHAFTS, REAR AXLES AND REAR TREAD WIDTH

A. O.E.M. production manufactured 2 to 4 speed transmissions that are cataloged through dealer channels will be permitted. Bert, Brinn, or Falcon circle track transmissions are permitted.

B. All transmissions must have at least 2 speeds forward and one reverse.

C. No 5 speed, over drive or automatic transmissions allowed.

D. All transmissions must bolt directly to the rear of the bell housing which bolts directly to the rear of the engine block.

E. Only steel driveshafts and universal joints that are in a similar design to standard production will be permitted.

F. All drive-shafts must be painted white.

G. All cars must have a 360-degree hoop toward front of drive-shaft, made of at least ¼ inch by 2 inch steel strap.

H. It is recommended to have a drive-shaft safety hoop built out of 4 or 5-inch diameter by 6 inch long round tubing.

I. Full floating rear ends are compulsory.

J. Rear end coolers may be used, but cannot be mounted inside of the driver’s compartment.

K. No open tube rear ends allowed.

L. No cambered rear ends permitted.

M.     The rear tread width can be no wider than the front tread width. (Both sides) 

N.      Axles must be made of steel only.

SECTION 9:  BATTERY, MIRROR, WINDOW NET, SEATBELTS, RADIATOR, FAN BLADE, WATER PUMP, AND OIL COOLER

A.  All batteries must be mounted in a safe and approved manner.

B. No mirrors permitted outside of car.  Only one mirror allowed.  To be mounted in the center of the windshield.  Maximum size 3 inch by 5 inch.

C. All cars are required to have an approved window net in the driver’s door.

D. All cars are required to have a lap belt, crotch belt, and 3 inch shoulder harness.

E. All belts must be securely fastened to the frame of car.

F. Only 1 radiator permitted for the purpose of cooling water.  Radiator must be mounted in front of the engine.

G. Water pump must mount in stock location.

H. No electric fans permitted.  No flat bladed fans permitted

I.  Oil reservoirs must be mounted in front of rear end housing.

J. Oil reservoirs or oil coolers cannot be mounted inside of driver’s compartment.

SECTION 10:   ROOFS, BODIES, AND NOSE PANELS

A. Bodies must be mounted in a similar manner to stock appearing.

B. Aftermarket production manufactured nose panels must be mounted in approved manner.  The front and sides of nose panel cannot be cut or altered, with the sides mounted no lower than 4 inches from the ground with the car at racing height.  The sides of the nose panel must be parallel to the ground.

C. The racetrack officials must approve any bars ahead of the nose panel.

D. Roofs may be made of fiberglass or aluminum, but must meet specifications as set forth in the rules and must be         approved by the officials.

E. All roof panels must have front mounting posts and rear roof panels.

F. The front roof posts will be required to be a minimum of (1) one inch wide and a maximum of (2) two inches wide.  Left and right side will be required to go to the outer rear corner of the front fenders. 

G. Rear roof panels must be mounted as per diagram on the reverse side of this sheet.

H. Rear roof panels will be required to extend out to the quarter panels.

I. Left and right side rear roof panels must be the same length and design.

J.  Car or opening covers are only permitted in case of inclement weather. 

SECTION 11:  REAR SPOILERS AND REAR DECKS

A. All competing makes and models will be permitted to use a one-piece solid rear spoiler 8 inches in height.

B. All spoiler measurements will be made from the deck and will be a measurement of all spoiler material.

C. All competing models will have a maximum rear spoiler width of 72 inches.

D. All competing models will be permitted to use 3 spoiler braces.  Spoiler braces may be 18 inches maximum at base but cannot extend past the rear roof posts.

E. All spoiler braces will be required to fit the track’s template, to be no higher than 3 inches at the front of the base and can be no higher of extend rearward past the rear spoiler.

F. Spoiler braces will be permitted to have up to a ½ inch break in them.

SECTION 12:  WEIGHT RULES

A.  All weight must be in block form of no less than 5 pounds, and must be painted white with the car number on them.

B. All weight must be bolted to the frame of the car in a secure manner.  Should use at least (2) ½ inch bolts for each weight that is bolted to the car.  No weights over 50 pounds permitted.  No weight can be bolted to the rear bumper of the car.  No stacking of weights permitted.

C. Any weight mounted behind the fuel cell must be mounted below the frame of the race car.

D. No mounting of weight inside of the driver's compartment or above the interior of the car permitted.

SECTION 13:  CHASSIS AND EXHAUST

A. Round tube headers only.  All primary tubes must go directly into one collar   at the same point and end of header.  Must remain dual exhaust with no crossover or Tri-Y pipes.

B. All headers must have collectors on them and must exit under car and   pointed toward the rear of the car.

C. All competing models will be required to use mufflers to meet maximum noise level of 98 D.B.A. at 100 feet.

D.  All front suspension must be of A frame type.

SECTION 14:  WHEELS AND BRAKES

A. Steel or aluminum wheels will be permitted.

B. Maximum wheel width is 14 inch.  Bead locking devices permitted on all 4 corners.

C. Steel or aluminum calipers may be used.

D. Rotors or brake drums must be made of steel.

E.   No ceramic or any other coating permitted on surface of rotors or brake drums.

F. Only approved foam or disc type wheel cover will be permitted.

G. All brake lines must be metal.  No plastic lines.

 SECTION 15:  TIRE RULE

A. The tire rule will be Hoosier WRS or WRS 2 D-55.

B. 11.0/88, 11.0/90, or 11.0/92  only will be permitted.  No grooving, softening, or siping of tires allowed.

C. You may only use sandpaper up to and including 24 grit to remove the glaze on the top layer of tires.  When you are completed with sanding of tires, the edges of the tread block must remain the same as the edge of the block next to it. You will only be able to create the look of a worn tire, and not something of a different tire face appearance.  (Example: no wavy tread pattern or deep grinding will be allowed.) Metal grinding disks are not permitted.

EIRI- (Except in rare instances) Decisions of officials are final and binding without exception! Any rule changes or clarifications during the course of the year will be published at www.acspeedway.com and will be considered as an official part of rules.

Changes or clarifications in rules are in red print.