NASCAR LKQ Pick Your Part Late Model Rules – 2018




The ABC Body Rulebook version 9.0 will be used. (

A) No lightweight hood allowed. Add 15# for lite weight hood.
B) Holes for ducting are permitted in the front air dam for air inlet only.
C) Lower radiator panel must be no wider than 29”going forward from radiator to nose.
D) At all times, the ABC “A” measurement must maintain a min. length of 11.5 inches.
E) At all times, 20” is the minimum length from the bottom of the nose up to the hood seam.
F) Spoiler must be 6 ½” x 60” with four (4) inches of the top of the spoiler must be clear.
G) The spoiler must be slotted ½ inch in the center to fit the NASCAR overall body template.
H) No roof rails.
I) ABC manufacturer standard mesh grill screen only.
J) No under car panning outside frame rails and no further than (a) post and (b) post.

H) No tire blowers allowed.
I) Pre race minimum 4” ride height without driver. Postrace minimum ride height 3.5” without driver.

Option (1) – GM 604 Crate Engine (Sealed from Factory) must be run as delivered from GM with all applicable GM factory seal bolts intact. No altering or rebuilding allowed. Must have correct GM harmonic balancer. Rocker arms, valve springs, retainers and keepers must all be as delivered from factory. A 6.5” oil pan permitted. Base weight 2875# – 57% left side at all times.
Option (2) Approved Vendor Sealed 604 rebuilt to GM yellow book specifications. 2900# – 57% left side at all times.
The approved engine vendors are:

 The Loe Pit Stop – 661-829-2140
 JMS Racing Engines – 626-579-4567
 Van Dyne Engineering – 714-847-4417

A) Must use a gauge legal Holley 650 CFM, 4bbl, P/N 80541-1 carburetor.
B) Must use a metal one (1) inch thick carburetor spacer with 4 square cut holes.
C) Crankshaft centerline must be centered in the front clip rails.
D) Engine setback 1.5” behind furthest forward spark plug on driver side behind upper ball joint.
E) Only round uncoated metal air filter housings permitted. Cold air boxes are not allowed.
F) A shield may attach to the front area of the air cleaner up to half the air cleaner.
G) Any device that may control the flow of air will not be permitted inside of the air- cleaner.
H) Stock OEM type HEI distributors only. Remote ignition box add 10# (non HEI).
I) 12 Volt Electrical System Only.

J) No traction control devices.
K) Any car/driver found with traction control device will be suspended for a minimum of 1 year.
L) Radiator must remain in the standard position not to exceed two (2) inches from vertical.
M) Radiator overflow outlet hose must exit at the right lower corner of windshield area.
N) Dry sump oil systems will not be permitted.
O) Any 1.625” headers allowed. Catalog Part Number required.
P) No Tri Y headers. No stepped headers. No merge collectors.
Q) Stainless Steel headers not permitted.
R) Exhaust pipes from header to “X or Y” must be no larger than three (3) inches in diameter.
S) Exhaust pipes exiting must be no larger than five (5) inches.
T) Exhaust tubing exiting “X or Y” cannot be smaller than the tubing in front of it.
U) Pipes must be securely fastened to the frame with a minimum of two (2) bolts.
V) Exhaust pipes must extend past driver and either turn down or exit to outside of car.
W) Mufflers must maintain a maximum of 90 decibels at 100’.
X) Mufflers must be in place at all times.

Kern Raceway Engine Option (3) Any rebuilt GM 604 Crate Engine 360ci, 10.0:1 compression, must run a 1” Governor Restrictor Plate with 1.00” inserts. 2925# – 57% left side at all times.
Kern Raceway Engine Option (4) – steel block, wet sump, 11.5:1 max. compression, max. 361 ci, 2 bbl Holley 4412, with Irwindale Brodix head or Vegas spec Vortec head, Must run a 1.25” restrictor plate supplied by Irwindale Speedway. 2925# – 57% left side at all times.
Option 5 – GM Factory Sealed 602 Engine – 2800# and 57% left side at all times.

CT 525 – add 40 in front of bellhousing with 2 bbl holley 4412 carburator and 1.25” restrictor plate with 6600 rev chip. 2925# – 57% left side at all times.

A) Heavy duty racing style clutch and pressure plate recommended.
B) 7.25” clutch with minimum of 2 discs. 5.5” clutch add 15#
C) No direct coupling type units.
D) Steel bell housing only. Aluminum bellhousing add 10#
E) Transmission must have two forward gears and working reverse.
F) Any aftermarket transmission allowed.
G) Minimum weight of transmission is 50# without shifter.
H) OEM 3 or 4 speed transmission – Saginaw, Muncie or T-10 with heli cut gears allowed.
I) Third gear ratio minimum 1.18 to 1. High gear 1 to 1. Must not circumvent gear rule at any time.
J) One-piece magnetic steel drive shaft with a minimum 2.75” a minimum thickness of 0.060”.

J) It is mandatory that two 1/8-inch x 1-½ inch steel drive shaft hoops front and rear.
K) All drive shafts must be painted white with car number on it.
L) 9-inch floater or quick change allowed.
M) Third member including bearing retainer and yoke must be magnetic steel.
N) Mandatory rear gear 4.71 for all cars.
O) Solid magnetic steel axles only.
P) No cambered snouts or bolt on snouts.
Q) Gun drilled axles add 15#
R) Any 15” x 8” steel wheel.
S) Wheels must weight a minimum of 17 pounds.
T) The use of bleeder valves is not permitted.

A) Tires must be purchased from Irwindale Speedway.
B) Approved tire is Hoosier 970 – 8”. No Star tires.
C) Tires will be scanned and logged to each car.
D) Tires that have been altered by any means will not be permitted. No tire shaving.

Tire Rule:

1) At a competitors first event of the season he/she will be may purchase five (5) new tires.
2) At each race after the competitors first race he/she will be allowed one (1) recorded tire.
3) You must present a sticker tire to be scanned and logged.

3) You must race the tire the night you scan/log it in for competition.
4) You must qualify and start the race on logged/scanned tires.
5) You must practice on 970 tires.
6) Damaged tire must be presented to Track Officials at the end of the night for evaluation.
7) Irwindale Speedway reserves the right to impound tires for storage between events.
8) Any attempt to circumvent tire rule will result in penalty.
9) It is the race team’s responsibility that an official scans/logs their race tires.

A) Any perimeter chassis may be used similar to the All-American Series Rule Book Frame Requirements
B) Roll cage must be constructed in a manner similar to the diagram in the back of the current NASCAR All-American Series Rule Book. A full roll cage is required.
C) Must have four (4) bent door bars on the both sides of car. Top right door bar can be straight.
D) Main roll cage, see NASCAR All-American Series Rule Book diagrams – must be 1.75” x .090” minimum,

two (#13) rear down bars and two (#16) front sub frame bars must be 1-¾ inches x .090 inch minimum round magnetic steel tubing.

E) The driver’s side door bars must be plated with a steel 1/8-inch material from a to b-pillar.
F) Rear frame rails may be 2-inch x 2-inch x .095-inch square tubing from the rear end to the back.
G) Interior panels except crush panels must be fabricated of 24-gauge magnetic steel minimum.
H) Interior panels must be trimmed neatly around roll cage and sealed for safety.
I) Interiors panels must be painted and must fit properly and free of sharp edges.
J) Interior right side door shelves not permitted.
K) Added weight must be in block form of no less than 10 pounds.
L) All added weight must be securely bolted in place with a minimum ½-inch diameter, grade 5 bolts.
M) All added weight MUST be painted white and the car number must be clearly visible on each piece.
N) Weight may not be added ahead of the front spindles, or behind the rear axle.
O) Lead enclosed in a frame rail must have two 3/8-inch grade 8 bolts as a secure stop at each end.
P) Deduct 25# for a stock clip and 25# for leaf spring rear suspension
Q) Add 1% left side weight for a stock clip or leaf spring car
R) Straight rail chassis (under 56” OD frame rail width) deduct 1% left side weight (56%)
S) Strut type two piece lower a-arm and rack and pinion steering – add 20# penalty
Approved tubular front replacement clips:
1) Port City Racing, P/N 100-2-205.
2) Race Car Factory, P/N 5506.
3) Victory Circle, P/N VCC-02-8055.
4) Jackson Race Car, P/N 75.
T) Approved front clip with steering rack – add 15# to left clip rail were steering box would be.

A) Front coil springs must maintain a 5-1/2” minimum outside diameter plus/minus ¼”
B) All A-arms must be made of magnetic steel.
C) Lower A-arms must be same length. (+/- ¼”)
D) One-piece, non-adjustable, heavy-duty magnetic steel spindles must be used.
E) Wheel bearings must be magnetic steel, tapered roller bearings only.
F) Wide five pattern hubs – add 25#.
G) Tread width must not exceed a maximum of 67” center to center at spindle height.
H) A minimum 105” wheelbase, must be within +/- ½-inch on opposite side.
I) All steering components must be magnetic steel. Tie rod adjuster sleeves may be aluminum.
J) Sway bar must be one-piece magnetic steel only.
K) Sway bar must not be adjustable from inside.

L) Sway bar for rear axle not permitted.

M) Trailing arms and top link must be one piece tube. Trailing arms must be equal length+/-1/2”
N) Rubber bumpers, springs or spring loaded bars will not be permitted.
O) Panard bar adjuster can’t be within drivers reach.
P) Rear coil springs must maintain a 5” minimum outside diameter plus/minus ¼”.


A) Shock absorbers and components must be used as supplied by the manufacturer.
B) Adjustable shock mounts of any type will not be permitted.
C) Shock body and shaft must be made of magnetic steel.
D) Shocks must be an emulsion type shock only.
E) When shocks are compressed, they must remain compressed at ambient temperature.
F) Only one shock per wheel is permitted.
G) No external reservoir type shocks allowed.
H) External adjustments will not be permitted on any shock.
I) No gas charged shocks. Gas charged shocks add 40#
J) All shocks must be available to all competitors through a catalog number.
K) Approved shocks:
1) QA1 Steel 50/51 Series.
2) Advance Racing Suspensions 2000 Series

All downward chassis movement while the race car is in competition must be limited only by normal increasing stiffness of the springs or the bottoming of the chassis against the race track, whichever occurs first. Any travel limiting device or procedure that in the judgement of track officials attempts to distract from or compromise the above will not be permitted. Any device such as chains, cables, or blocks that limit the travel of the suspension either up or down will not be permitted. When jacking the car, a minimum of 1.5” of suspension droop is required. Racecar must come up to minimum 3.5” ride height by itself at all times without assistance.

A) Single piston magnetic steel brake calipers only.
B) OD Scalloped or drilled brake rotors are not permitted.
C) Brake cooling air must come through the nose of racecar.
D) Aluminum brake calipers add 15#
A) All cars must compete with fuel purchased and dispensed from the track.
B) Fuel must be ran as dispensed. Subject to fuel sample at any time.
C) Sunoco 110 octane standard is the spec fuel. No fuel additives.
D) The fuel cell must be completely enclosed in a magnetic steel container.
E) Fuel cell must be ten (10) inches off the ground at all times.
F) Fuel cells must be centered between frame rails.
G) A steel fuel cell cage must be fabricated from a minimum of 1”x 1” x .065” square tubing.
H) A minimum of two (2) straps lengthwise and two (2) straps crosswise must completely encircle the fuel cell. The material for this strap is 1”x 1” x .065” square tube.
I) A fuel cell protector bar made from a minimum of 1-½” inch by .065 steel tubing is required.
J) Fuel pump must be mounted in stock location.

Refer to Whelen All American series rule book section 6 for covering protective clothing.

A) It is recommended that all cars have a built-in, fully charged fire suppression system.
B) All entrants must have a 10-lb. fully charged fire extinguisher in their pit area.
C) Helmets must be SA 2010 or SA 2015.
D) Head and Neck Restraint mandatory.
E) All seat belts must be a complete matching set from the manufacture.
F) Belts must be dated by manufacturer within 2 years of new.
G) Seat belt mounting and installation: refer to the current NASCAR All-American Series Rule Book.

H) Center of steering wheel must be padded with 2-inch of resilient material.
I) All steering columns are required to have a collapsible section.
J) One (1) inch ribbon style window net mandatory with an approved quick release at top.
K) Window net must be within 5 years of manufacture date.
L) All cars must have only one (1) rear view mirror.
M) An additional rear view spot mirror may be added.
N) No mirror may extend outside of the body.
O) A labeled on/off master switch is required and be accessible from both sides of the car.
P) Two-way radio communication is mandatory whenever the racecar is on the track.
Q) Radio frequencies must be cleared by the Irwindale Speedway radio vendor prior to competition.
R) Each competitor must have a spotter in the designated location.
S) Your spotter must monitor Irwindale Speedway race control.
T) One car radio, one wiring harness, and one antenna only
U) A professional racing seat is required.
V) Seats must be mounted with a minimum of (6) 3/8 inch grade 5 bolts. Two bolts must be located at the front of seat and two on bottom rear and two at #7 roll cage bar at upper seat back (see NASCAR All-American Series Rule Book diagrams).
W) It is recommended that the seat also offer rib protection and have leg extensions.
X) Headrest recommended on both sides of head.

Any part found at any time at any NASCAR sanctioned event that does not meet applicable
NASCAR/Irwindale Speedway rules, must be surrendered to the Irwindale Speedway Tech Official at that time, and will not be returned. No equipment will be considered as having been approved by reason of having passed through inspection.