SAFETY EQUIPMENT:

All Safety Equipment is Subject to Track Inspection and Approval, applies to all times car is on
the track including packing.
Snell-Rated Helmet in Good Condition, SFI-Approved full fire suit, fire retardant gloves, shoes
and neck brace (or head and neck restraint system) required.
Minimum three inch wide SFI-Approved Five Point Safety Belt assembly required (2 inch with
head and neck restraint system) and must mount securely to main roll cage.
Fire-resistant Roll Bar Padding required on any part of Roll Cage Driver may contact with while
buckled in.
Driver-side Window Net required, Minimum 16 inch by 20 inch ribbon or mesh style, and must
be mounted to roll cage so latch is at Top and Front of driver’s window opening.
Recommend: Safety Belts to be no more than two years old, fire retardant head sock and
underwear and collapsible steering shaft.

FRAMES:

105” minimum wheelbase 110” maximum wheelbase 1” tolerance forward or backward .
Front Clips may be of OEM Stock Clip design or Fabricated 2”x3” Clip built to GM Camaro
Specifications.
If running 2”x3” fabricated front clip you must add 25 lbs. of weight in front of most forward spark
plug hole. Left or right side of car.
Front Clips must be of A-Arm configuration, both upper and lower.
Front frame extensions cannot be any larger than 2 inch wide x 3 inch height by .083 inch
thickness steel magnetic tubing welded at a point of 2 inches in front of steering gear box, must
angle down at a maximum angle of 18 degrees.
Stock front clipped cars center main frame section beginning at main cage front mounting points
may be constructed with minimum of 2 inch x 2 inch x .095 square or minimum 1.75 inch round
OD x .095 steel magnetic tubing.
Rear of Main Frame may be wider or narrower than front of frame.
X-Bracing is allowed.
Front GM Type or Ford Front Fabricated Clip Specifications, Subject to I-37 Track Official
Inspection and Approval

ENGINE LOCATION:

Minimum Height – 12 inches from ground to center of crankshaft.
Setback – 1 ½ inch from center of left upper ball joint to most forward spark plug hole.

ROLL CAGE:

Must be of four post design and consist of continuous hoops with a minimum roll cage piping
size of 1.5 inch OD x .095 thick magnetic steel tubing.
Main cage rear hoop must have a minimum of one horizontal bar and one diagonal bar from top
of hoop to bottom of down post.
Main roll cage hoop and halo must be a minimum of 1 inch above drivers head with helmet on
and driver buckled in car.
Main cage front uprights must tie together with a minimum of one horizontal bar.
Front left and right kickers required from main cage to in front of engine.
Rear left and right kickers required from main cage to rear frame section.
Front and rear loops allowed.

DOOR BARS:

Minimum of three driver’s doors bars minimum of 1.5 inch OD x .095 magnetic steel tubing
parallel to frame and perpendicular to driver, must have a minimum of two uprights intertwined
into horizontal doors bars from frame to top door bar to strengthen door bar system.
Foot protection required.
Steel door plate of 18 gauge or 0.0049 inch minimum thickness must be securely welded to
driver side door bars and cover area from top of door bars to frame and from rear down post to
5 inches in front of seat, may be welded into door bar system design.
Minimum of one diagonal bar or X-Brace must tie right front upright to rear hoop down bar on
passenger side.

BODY:

Any Steel, Aluminum or Fiberglass Body allowed.
MD3 Dirt Late Model Body recommended.
Rear Spoiler not to exceed 10 inches in material height, may be Lexan.
NO Nerf Bars Allowed on the outside of the body. Cars must be keep neat appearance; any
loose or flapping body panels may cause car to receive mechanical black flag and will not be
allowed to compete until repair is made.

DRIVER COMPARTMENT:

Minimum three windshield bars in front of driver. Lexan or aluminum cowl panel in front of driver
allowed, but can be no wider than cockpit and no farther back than steering wheel. Driver must
be sealed off from track, driveline, engine, fuel cell, suspension components, battery, coolers
and fuel lines. Aluminum high back racing seats required, must be bolted in with a minimum of 4
0.375 inch bolts.
NO rear view mirrors.
NO driver-adjustable devices allowed while car is in competition except brake adjuster and right
front brake shut-off.

SUSPENSION:

Front
Steel aftermarket Spindles and Wide Five Hubs allowed, Aluminum Spindles not allowed.
Tubular upper control arms allowed and can be adjustable.
Lower control arms may be aftermarket steel stock or stock mount type, may be heim end.
Weight jacks allowed, cannot be adjusted from inside driver’s compartment.
Coilovers allowed.
Sway bar allowed but cannot be adjusted inside driver’s compartment.

Rear
Steel Coil Springs, Coilovers OK, Steel or Composite Leaf Springs OK.
Weight Jacks cannot be adjusted from inside driver’s compartment.
Configuration may consist of a Three Link, OEM Chevelle Type Four Point, Swing Arm or of
Leaf Spring configuration including Mono Leaf/Coil Over design.
NO Four Links, Z-link, or Jacob’s Ladder.
NO Independent Rear Suspension.
NO lift, brake or rear sway bars.
All suspension components may be steel or aluminum, including heims.
Trailing Arms may consist of steel radius rod design, cannot be bushed, cannot extend or
collapse other than by manual adjustment of heim ends.
Pan Hard or J-Bars allowed, may be adjustable, J-Bar may be rubber bushed.
One mechanical pull bar allowed may be of a single spring or biscuit design.
One single steel or aluminum bodied shock may be mounted above pull bar from rear end and
must mount forward of rear end.
Shocks:
Any Steel or aluminum bodied shock allowed.
NO adjustable shocks, NO remote reservoir shocks, NO air shocks, NO Schrader or Bladder
type shocks.

STEERING:

OEM type Steel Steering Component Configuration or Rack and Pinion.
Note: Rack and Pinion must bolt 10 lbs of ballast weight in place of gear box.
Steering gear box must bolt in stock location on OEM clip or in OEM position on any fabricated
clip.Quick Steer Ok.
Aftermarket Center Links and Tie Rods steel or aluminum allowed including Tubes and Heim
Ends.
Quick release Steering Wheel required.

BRAKES:

Aftermarket brake systems allowed including brake pedals, master cylinders, calipers and pads.
Calipers may be steel or aluminum and be of single or dual piston design.
Brake bias adjuster allowed and may be accessible in driver’s compartment.
NO Carbon Fiber Brake parts.
Cooling holes maybe drilled in rotors.
Right front brake shut off allowed and may be accessible from driver’s compartment.

ENGINE:

Block OEM or Aftermarket Cast Iron V-8 Small Block with a Maximum of 364 CID.
Block must remain as cast, absolutely no lightning of any kind to block.

604 crate Motor allowed. Must add 25 lbs of weight in front of transmission

NO V6 or Big Block Engines.
Lifter valleys may be deburred, valley vents and screens may be installed.
No enlarging or bushing of lifter bores.
Wet Sump Oiling only NO Dry Sump or any type External Oil Systems allowed.
Aftermarket Steel Oil Pan allowed, with mandatory 1” inspection hole to allow inspection of
crankcase area.
Windage Tray OK
Aftermarket Balancer OK
Aftermarket Engine Bolts allowed.
Water Pump must be belt driven, can be cast iron or aluminum.
Crankshaft
Any Steel or Cast Iron Crankshaft allowed as follows:
2.0 journal cranks are allowed. NO Honda journal cranks.
Minimum Weight of 48 lbs.
Knife edging, contouring or stream lining is not allowed.
All Crankshafts must be within .060 of OEM specifications on rod and main bearing journals.
NO small journal Crankshafts allowed.
Pistons/Rods
Any flat top or dished pistons allowed.
Must have Steel wrist pins.
NO part of piston may rise above block deck.
Connecting Rods must be Steel, can be of cap screw or bolt design.
Cylinder Heads/Intake
Any Cast Iron 23 degree Head on GM, 20 degree on Ford. Ford N head is allowed
Any CC allowed.
Intake and Exhaust Ports must remain as cast, No porting/polishing.
Gasket Matching allowed not to extend more than 3/8 of an inch into port.
Stamped Steel, Roller Tipped or Full Roller Rockers allowed, any ratio.
NO Shaft Type Rocker Arm assemblies allowed.
Stud Girdles allowed
Valves must be steel, No Titanium Valves allowed.
Timing Chain and Gears, may be of Double Roller design, NO Belt or Gear Drives.
Any Aluminum Intake.
Camshaft and Lifters
Any flat tappet Cam with OEM stock diameter Lifters.
NO Roller Cams or Roller Lifters allowed.
Mushroom or Radius Lifters not allowed.
Push Rods must be steel.
Rev Kits allowed.

CARBURETOR:

Single (1) Maximum 750 CFM Vacuum or Mechanical Secondary or below allowed.
o Aftermarket billet aluminum metering blocks OK.
o May be modified to run Methanol or E85.
o Throttle blades or throttle shaft must retain stock thickness and is subject to Go/No-Go gauge
inspection
o Additional holes or passages are not allowed.
Screws or linkages on vacuum secondary carburetors may mechanically force open
secondaries.
Carburetors must have two (2) throttle return springs.
Carburetor Spacer not to exceed 1.250 inch including gaskets.
NO Aerosol type Carburetors allowed.
NO type of forced air induction allowed.
NO cool cans allowed.

FUEL/FUEL CELL:

Racing Fuel, Methanol or E85.
Smell enhancing additives OK.
All cars running methanol must have letter “A” on drivers side sail panel. Minimum of 4” in
height. This is MANDATORY.
NO performance enhancing additives or pressurized fuel systems allowed.
Racing Fuel Cell Required.
Maximum 32 gallon capacity and must be enclosed in a 20 gauge steel container.
Must mount between rear frame rails and behind rear end, bottom of cell can be no lower than
center section of rear end.
Must be properly supported and protected, must be minimum of 1.5 inch tubing loop to protect
bottom of fuel cell.
Must mount with minimum two solid steel straps surrounding entire fuel cell, 2 inches wide by
0.125 inches thick.
Fuel Cell vents including cap vent must have check valves.
Fuel Shut Off recommended.

TRANSMISSION/DRIVESHAFT:

Transmission
Aftermarket Transmissions are allowed, Bert, Brinn and Falcon.
Must have a minimum of two forward speeds, reverse and neutral.
Standard production OEM 3 or 4 Speed Transmissions allowed.
Explosion proof steel bell housing minimum 180 degrees around top of clutch and flywheel must
be used with all external clutch type transmissions.
Mini Clutches OK.
Powerglide Transmissions with Coupler OK, must have SFI Steel Flex Plate, and SFI Steel
Flexplate Shield. SFI Transmission Scatter Shield recommended.
NO In and Out Boxes.

DRIVESHAFT:

Steel Driveshaft with minimum diameter of 2 inches.
Cannot be carbon fiber, aluminum, or any other material other than steel.
Must be painted white with car number in contrasting color.
360 degree front drive shaft loop required within 6 inches of front U-joint, minimum .025 inch x 2
inch steel.

EXHAUST:

Any bolt on header with no adapters.
Must be of collector type only.
RADIATOR/ENGINE COOLING:
Radiator must be mounted in front of engine, between frame rails and have protection.
Cooling fan must be water pump mounted and fan driven, NO electric cooling fans.

REAR END:

Quick-change Rear-Ends or 9 inch Ford Full Floaters allowed.
Quick change must use 10” ring gear with aluminum or steel spool.
Quick change must use minimum one inch wide spur gears and bolt on rear cover.
Axle tubes may be aluminum or steel.
Center Section of Ford 9 inch may be aluminum.
Rear Ends must be locked.
Any full or mini spool allowed.
NO torque dividing differentials, scalloped ring gears, or cambered rear ends.
Rear end coolers allowed.

BATTERY & STARTER:

Battery must be securely mounted to chassis, between frame rails with positive terminal
covered.
Starter must be in working order and car must start under own power.
Note: Car must leave staging area on demand and unaided, any car which causes a delay in
starting or restarting of race due to starting issues will be put to back of that race.

ELECTRICAL & IGNITION:

Electrical
A master battery power Kill Switch is required and should be mounted within easy reach of
driver and be accessible from outside of car by track personnel, must be labeled Off/On.
When switch is in Off position all electrical power to car must be disconnected.
Alternator is optional, switch must also disconnect power to alternator if equipped.
Ignition switch must be mounted within reach of driver and outside of car by track personnel and
must be clearly labeled.
Ignition
OEM Stock HEI or MSD Ignition Systems allowed.
External Ignition Boxes Ok, (6A, 6AL & 6ALN) only one box per car, out of reach of driver.
NO Magneto ignitions allowed.
Absolutely No Electronic Traction Control of any kind, end result will be DQ, forfeit of all
winnings/points and an automatic 1 year suspension.

WHEELS & TIRES:

Steel Racing type wheels only, Aluminum wheels not allowed.
Bead Locks OK.
Maximum Wheel width of 10 inches.
Any 11 inch Tire allowed any compound.
Wide Five hubs and wheels allowed.
Air pressure relief valves not allowed.
Chemical softening or treating of any kind not allowed.
Tires may be grinded, sipped or grooved.

WEIGHT:

Minimum Weight – 2800 lbs.
Ballast Weight Must be painted white with car number, must be securely fastened with a
minimum of 2 ½ inch. steel bolts.

SCORING:

Car numbers must be a minimum of 24 inches in height and 4 inches in width, and be clearly
visible from scoring tower on both sides and top of car.
6 inch numbers on front and rear of car for line up procedures.
If you have any questions or require any clarifications please do not hesitate to ask.
Doug / I-37 Speedway Tech Director 210-331-1026
ALL cars are subject to track inspection and approval before entering into competition, and may
be subject for re-inspections.
Any car which is determined as unsafe will not be allowed to compete until safety issue is
corrected and car is declared safe for competition. I-37 reserves the right to clarify or amend
these rules as deemed necessary.