THE RULES AND/OR REGULATIONS
SET FORTH HEREIN ARE DESIGNED TO PROVIDE FOR THE ORDERLY CONDUCT
OF RACING EVENTS AND TO ESTABLISH MINIMUM ACCEPTABLE REQUIREMENTS
FOR SUCH EVENTS. THESE RULES SHALL GOVERN THE CONDITION OF SPEEDWAY
EVENTS AND, BY PARTICIPATING IN THESE EVENTS, ALL RACEWAY COMPETITORS
ARE DEEMED TO HAVE COMPLIED WITH THESE RULES. NO EXPRESS OR IMPLIED
WARRANTY OF SAFETY SHALL RESULT FROM PUBLICATION OF, OR COMPLIANCE
WITH THESE RULES AND REGULATIONS. THEY ARE INTENDED AS A GUIDE FOR
THE CONDUCT OF THE SPORT AND IN NO WAY ARE A GUARANTEE AGAINST INJURY
OR DEATH TO PARTICIPANTS, SPECTATORS OR OTHERS.
MODIFIED RULES APPLY
1. SAFETY EQUIPMENT: Rules apply at all times car is on track.
Snell-rated SA2005, SA2010 or SA2015 helmet required. Roll bar padding
required in driver compartment.
Recommended: Fire retardant padding. SFI-approved full fire suit
required. Fire retardant gloves, shoes and neck brace (or head and
neck restraint) required. Right and left seat head supports required
if using head and neck restraint system. Recommended: Fire retardant
head sock and underwear, collapsible steering shaft. 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 front of window.
Minimum three inch (two inch with head restraint system) wide SFI-approved
five point safety belt assembly required, must be mounted securely
to main roll cage. Recommended: Safety belts no more than two years
old. Kill switch required within easy reach of driver and must be
clearly marked ‘OFF’ and ‘ON’.
2. FRAME: (see frame drawing) 1964 or newer OEM perimeter American
rear-wheel drive passenger car frame only. No sport car frames.
Frame must be full and complete, cannot be widened or narrowed,
and must be able to support roll cage on both sides. Exceptions
are: weight jack in original center line of spring tower allowed;
frame may be cut a maximum 36 inches forward from center of rear
end housing; horns may be removed in front of steering box and notched
maximum one inch at bottom for tie rod clearance; front crossmember
may be notched and boxed for radiator and/or steering clearance;
maximum seven inch wide opening in side of spring tower for spring
removal. Maximum two inch wide by four inch tall frame stiffener
may be welded directly to outside of left side frame rail. See www.imca.com
for OEM frame dimensions. Minimum wheelbase 108 inches, maximum
112 inches, both sides. Maximum overall width shall not exceed 78
inches from outside of tire to outside of tire. No part of frame
can be lower than four inches from ground except front crossmember.
3. ROLL CAGE: Must consist of continuous hoops, minimum 1.75 inch
O.D. tubing, with minimum wall thickness of 0.095 inch for main
cage, frame-mounted in at least six places.
Recommended: low carbon or mild steel. Must consist of a configuration
of front, rear and top hoops connected by tubing on sides or side
hoops. Driver’s head must not protrude outside cage with helmet
on. Roll cage must be securely supported and braced with minimum
one cross bar in top halo. Foot protection bar required. Main cage
no further forward than rear of engine. All bars forward of cage
must be lower than hood.
4. DOOR BARS: All driver side door bars and uprights must be minimum
1.5 inch O.D. with 0.083 inch wall thickness. Minimum three driver
side door bars, parallel to ground and perpendicular to driver,
and welded to front and rear of roll cage. Passenger side must have
at least one cross door bar, horizontal or angled, minimum 1.25
inch O.D. with 0.083 inch wall thickness, and one top door bar,
minimum 1.5 inch O.D. with 0.083 inch wall thickness. Steel door
plate, 18 gauge or 0.049 inch minimum thickness, must be securely
welded to outside of driver side door bars and cover area from top
door bar to bottom door bar and from rear hoop down-post to five
inches in front of seat. Must be visible for inspection.
5. BODY: (See diagram) No composite or plastic body panels allowed
except roof rock guard and hood scoop. Body must be same width,
front to rear, and parallel to OEM frame.
Aluminum nose panel must be flat. Maximum 2.250 inch side fins
allowed on aluminum nose. IMCA-approved plastic nosepieces allowed.
Nose must be mounted in an approved manner and can extend no higher
than front top of hood. Nose piece must remain inside confines of
front bumper and be no lower than two inches below frame horns.
Cooling holes allowed. Engine compartment must remain open (no side
panels). Hood must cover radiator, be level or sloped down at front,
enclosed and maximum two inches above interior deck at rear. No
panel in front of right door to engine compartment. No inner panels.
No complete or half-car covers, rear tail cover allowed in personal
pit area only. Must have front and rear roof support posts. Driver
and passenger side windows must have at least 12 inch opening (height
and width), measured at center of window, between lowest point at
top and highest point at bottom. Sail panels may not extend ahead
of back of seat. Solid sail panels only. Roof must be fiberglass
or aluminum, full size and rounded down in all directions. No dished
roofs allowed. Driver roof hatch allowed. Maximum 1.5 inch rolled
down rock guard allowed on roof front. Maximum four inch roof sides
allowed. Maximum one inch ridge down sides of roof. Maximum one
inch rear roof stiffener (must face down). Rear spoiler allowed
with GM 604 crate engine only, maximum two inches in material height
and maximum 66 inches wide. Spoiler may have one-inch rear stiffener,
minimum one inch down from top. Spoiler must be attached to rear
of sail panels, with one optional two-inch by five-inch triangular
center support. No additional fins, lips, wings or vortex generators
allowed. Maximum four inch plastic skirting allowed on bottom of
doors and quarters. No reflective doors or quarter panels. Body
may be maximum one inch outside of rear tires (both sides) for clearance.
Car number must be minimum four inches thick and 20 inches tall
and clearly visible, on both sides and roof of car; six inches tall
on rear and front if possible.
6. DRIVER COMPARTMENT: Must have minimum three windshield bars
in front of driver. Lexan or aluminum cowl panel in front of driver
can be no wider than cockpit and no farther back than steering wheel.
Minimum 0.125 inch aluminum, or 0.060 inch steel, complete floor
pan required. Aluminum high-back seat only and must be bolted in,
using minimum 0.375 inch bolts, next to left side frame rail and
ahead of rear tires. Bottom of seat can be no lower than bottom
of frame rail. Driver must be sealed off from track, driveline,
engine, fuel cell, canisters and pumps. Oil coolers must not protrude
above interior. Accumulators cannot be mounted between driver and
left-side door bars. No driver-adjustable devices allowed while
car is in competition except brake adjuster. No mirrors of any kind.
7. FRONT SUSPENSION: All components must be steel, unaltered OEM,
in OEM location, and replaceable by OEM parts. Exceptions are: tube-type
upper A-frames with or without aluminum or steel cross shaft, and
mounts can be moved; stamped steel OEM replacement lower A-frames;
rubber, nylon or steel lower A-frame bushings, no offset or bearing
type; one welded shock mount on lower A-frame; no screw jack type
shock mounts; OEM or OEM replacement rebuildable ball joints allowed.
Lower A-frames must be right and left, and of same design. Lower
A-frame mounts and bolt holes on frame must be within OEM specifications.
Sway bar must be unaltered OEM. No suspension stops of any kind
8. STEERING: No rack and pinion. All components must be steel,
unaltered OEM, in OEM location. Exceptions are: outer tie rod end
and adjustment sleeve may be replaced by a minimum 0.625 inch steel
rod end and steel tube; spindles can be ground for brake caliper
clearance only; unaltered, OEM or OEM replacement Pinto spindles
with ‘IMCA’ raised cast; replacement spindle with Speedway
Motors raised cast - part numbers 91034501-L and 91034501-R; bolt
on spindle savers allowed; steel steering shafts and knuckles only;
driver compartment steering may be modified, must be kept on left
side. Spindles must be right and left, and of same design. Quick
release required - steering quickener and steering wheel may be
aluminum. Idler arm, pitman arm, and center link must match frame.
9. SHOCKS: One steel, nonadjustable, unaltered shock per wheel.
All shocks must completely collapse at any time. One additional
shock allowed in pull-bar area. No external or internal bumpers
or stops. No threaded body, front coil-over, air, or remote reservoir
shocks. No Schrader or bladder type valve allowed. Front half may
be shielded. One or all shocks may be claimed per event for $50
each, counting as one claim on card, following shock claim procedures
(Refer to www.imca.com).
10. SPRINGS: One steel, non-progressive coil spring per wheel only.
One additional spring allowed on pull bar, may be progressive. All
coil springs must be at least 4.5 inches O.D. No torsion bars, air
bags, inner liners or spring rubbers allowed. Steel or composite
leaf spring allowed.
11. REAR SUSPENSION: No independent rear suspension. All components
must be steel. No covers on any suspension components. All trailing
arms/link bars must be solid tubing. Rear of frame may be altered
to accept leaf or coil springs. Steel coil-over eliminators, or
steel or aluminum coil-over kits allowed - must conform to shock
and spring rules. One mechanical traction pull bar allowed. No lift,
brake or sway bars. Rubber bumpers allowed on pull bar or panhard
bar only. No suspension stops or adjustable underslung of any kind
allowed. Exception is: solid safety chains securely mounted frame
to axle housing only (cannot be mounted to any floating device),
no springs or rubbers allowed. Minimum 19 inch long panhard bar,
measured straight line, center to center.
12. REAR END: Any steel approved OEM passenger car or truck rear
end allowed (housing and carrier). OEM rear end must use steel spool
(full or mini). Steel axle tube quick change 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. Safety hubs (floater) allowed. Steel axles only. Any additional
components must be steel, except lowering blocks, axle caps, U-joint
caps, and one piece drive flange. One inch inspection hole required
in housings. No torque dividing differentials, scalloped ring gears
or cambered rear ends.
13. BUMPERS: Steel bumpers must be on front and rear and welded,
or securely mounted with minimum 0.375 inch bolts. Rear bumper must
be capped, constructed of solid square, or minimum 1.25 inch O.D.
tubing with 0.095 wall thickness (similar to diagram), maximum six
inches beyond rear deck, no wider than five inches outside of rear
frame rails. If wider than five inches outside rear frame rails
must be bent forward 90 degrees, or constructed in a loop design.
Must have at least one upright, minimum 1.25 inch with 0.065 wall
thickness, from bumper to fuel cell guard. Two-bar front bumper
must be minimum 1.25 inch O.D. tubing with minimum 0.065 wall thickness
(maximum 0.095 inch) mounted frame-end to frame-end, no wider than
width of material outside frame horns and with bottom loop parallel
to ground. Top bar must be directly above bottom bar, minimum 6.5
inches apart, measured center to center.
14. TIRES/WHEELS: Must use unaltered Hoosier Race tire, G60-15
with IMCA stamped on sidewall. No chemical softening, conditioning,
or grooving of tires (refer to www.imca.com for automatic penalties).
Tires may be ground or siped within confines of tread (not past
factory straight line). No re-caps. All wheels must display white
‘IMCA approved’ decal and wheel manufacturer decal.
Aluminum, composite or steel spacers allowed. May use IMCA approved
bead lock, on right rear only. External, steel bead lock only and
it cannot make wheel any narrower than eight inches and no wider
than 8.75 inches. Must use only steel bolts. Foam type or plastic
outer mud cover allowed on right side wheels. Inner mud cover allowed
on left rear only. Rim-mounted bleeder valves allowed. Steel lug
* No Chemical Altering! Any car caught not meeting
minimum or maximum durometer requirements will be disqualified from
that event without protest.
Any car caught removing numbers or plates on tires indicating manufactures
identification will be disqualified without protest.
Tires may be tested at any time throughout the night’s events
and tested by officials by whatever means necessary.
Officials may request that samples be cut from any select tires
at any time, sealed, bagged, and signed by representative of team.
Samples may be sent to lab of tracks choice for testing and results
from that lab final. No appeal. No exceptions.
Tires detected by vapor analyzer (Sniffer) exceeding 700 ppm track
benchmark will be considered contaminated and disqualified from
Tires tested 700 ppm in post-race tech will be tested maximum 2
more times in 10 minute window from initial test. A tire that falls
below that 700 ppm in 2nd or 3rd test will be passed. A tire failing
all 3 test will be considered contaminated and disqualified. This
ruling may be protested by driver or car owner only and requested
to have samples cut and sent to lab for full analysis at car owner
or drivers expense. Cost for this protest will be $150 (includes
testing, shipping & handling) and must be paid to track officials
and sampled before car leaves the tech area. At that time the race
results will be considered unofficial and no payout to protest cars
until results from lab testing are complete. Sampling process will
need to be cut by team’s groover and placed in sample bottle
by team member, bottle will be sealed by team member, and placed
in evidence bag never being touched by officials. Team will provided
all needed information for documentation. Official race results
will be pending lab results.
15. BRAKES: Must be steel approved OEM, operative four wheel, drum
or disc. Must maintain minimum OEM dimensions for hubs/rotors and
calipers, cannot be lightened. Bolt pattern may be changed. Larger
studs allowed. Rear rotors may be aftermarket 0.81 inch thickness
(new). Vented solid surface rotors only, no scalloped or ceramic
coated rotors. No brake shut-off or pressure sensitive devices.
One front to rear proportioning device allowed. Brake lines must
16. EXHAUST: Round tube headers only. All primary header tubes
must enter directly into one collector at same point at end of header.
Collector and turn down length maximum nineteen inches total. Schoenfeld
mufflers, stamped IMCA609, IMCA930, or IMCA935 must be used if track
has noise reduction rule of 98 dB or more. All exhaust must go through
mufflers, two per car, one per header. Valve covers and headers
may be modified for pan-evac system. No exhaust sensors, merge collectors,
extensions, inserts, cones or balance tubes.
17. FUEL SYSTEM: Mechanical or belt driven fuel pump only and must
be mounted at front of engine. Racing fuel cell required, maximum
32 gallon capacity, must be in minimum 20 gauge steel container.
Cell must be securely mounted behind rear axle, between rear tires,
minimum of four inches ahead of bumper, minimum of 10 inches above
ground. Must mount with minimum two solid steel straps around entire
cell, two inches wide and 0.125 inch thick. All cell mounts must
be steel, securely welded to frame/cage. Protective tubing must
cover rear and extend past both sides of cell. No part of cell shall
be lower than protective tubing. Fuel cell vents, including cap
vent, must have check valves. If fuel cell does not have aircraft
style positive seal filler neck/cap system - a flapper, spring or
ball type filler rollover valve is required. Pick-up must be on
top or right side of cell. One fuel filter allowed.
No cool cans. Air cleaner top/stud cannot direct air into carburetor.
No top flow air cleaner housings or cold air boxes. One naturally
aspirated two- or four-barrel carburetor only.
One carburetor adapter/spacer allowed, maximum 2.20 inches thick,
including gaskets. No adjustable throttle bore or sleeve-type carburetor
spacers. Fuel shut-off recommended.
18. FUEL: Gasoline or alcohol. Racing fuel and E85 allowed. NO
performance-enhancing additives. Upper cylinder lube allowed with
alcohol only. Fuel sample may be taken from any car at any time.
(Refer to www.imca.com for automatic penalties).
19. WEIGHT: Minimum weight limit of 2,450 pounds, no tolerance,
after race with driver in car. No weights and/or loose objects in
driver compartment, above interior deck or outside body. Weights
must be securely mounted to frame or roll cage and painted white
with car number on it. Must be attached with at least two 0.5 inch
bolts. No titanium, magnesium or carbon fiber products. Exceptions
are: carbon fiber rock guard, hood scoop, and magnesium quick change
center section. Solid steel fasteners only.
20. BATTERY/STARTER: One 12 volt battery only, must be securely
mounted between frame rails, and positive terminal must be covered.
Car must have capability of starting without being pushed or pulled.
Car must leave initial staging area on demand, unaided, or go to
rear of that race. Reverse-mount starters with OEM case transmissions
only, see transmission rules for specifics.
21. GAUGES/ELECTRONICS: No unapproved cameras, transmitting or
listening devices (exception is one-way Race Receiver radio by officials),
timing retard controls, or digital gauges (including tach). No electronic
monitoring computer devices capable of storing or transmitting information
except memory recall analog tach. Crate engine must use maximum
6,400 rpm rev-limiter. Claim engines must use maximum 7,800 rpm
rev-limiter. This may be accomplished using one, non-adjustable,
12 volt ignition box with one high-end rev-limiter chip, an external
setting, or an internal preset. Refer to www.imca.com for approved
ignition systems and rev-limiters. No electronic advance curve ignitions
allowed. No unapproved or additional ignition accessories allowed.
All components must be out of reach of driver, but with rev control
easily accessible facing up or out for inspection. All wiring must
be visible for inspection. No magnetos or crank triggers. No electronic
traction control devices (Refer to www.imca.com for automatic penalties).
22. TRANSMISSION/DRIVESHAFT: Must have at least two forward gears
and one reverse, plus a neutral position. With engine running and
car in still position, must be able to engage car in gear and move
forward, then backward. OEM production type or IMCA approved aftermarket
transmissions allowed - two-speed, three-speed, four-speed and automatic.
No five speed (or more) transmissions, ‘in and out’
boxes, or quick change devices allowed. Functioning shift levers
must be in OEM location on all OEM production type transmissions.
All belt drive pumps must be mounted on front of engine. Flexplates
must be full, steel, unaltered OEM, or OEM replacement. Flywheel/flexplate
must bolt to engine between clutch assembly and crankshaft and all
driveline components within bellhousing must rotate while car is
in any gear. Transmission must be one of the following designs:
OEM Manual: Must have a standard OEM case and working disc-type
clutch or approved cone or disc-type coupler inside an explosion-proof
steel bellhousing. One flywheel only, minimum 8.5 inch diameter.
Diameter of clutch disc must be a minimum of 5.5 inches. Clutch
assembly must be steel, except housing, which must be steel and/or
Bellhousing can have only a hole for throwout bearing lever or
hose, must be 270 degrees around top of clutch and flywheel area.
Standard or reverse mount starter allowed, must directly engage
Automatic: Must remain in OEM or OEM replacement case, with a functioning
OEM appearing pump. Aluminum OEM bellhousing may be replaced with
aftermarket explosion-proof aluminum bellhousing. Original OEM bellhousing
must have approved scattershield constructed of minimum 0.125 inch
by three inch steel, (1) 270 degrees around flexplate.
Aftermarket Manual: Must be IMCA approved, aluminum case, with
internal clutch. Refer to www.imca.com for approved transmissions.
Must bolt to explosion-proof steel bellhousing, and use full, steel,
unaltered OEM or OEM replacement flexplate with starter mounted
in OEM location. No coatings or paint allowed on transmission case.
No ball-spline transmissions.
Drive Shaft: Steel slip-yokes only. Minimum two inch diameter
steel drive shaft and must be painted white. 360-degree drive shaft
loop required and must be constructed of at least 0.25 inch by two
inch steel, or one inch tubing, mounted six inches back from front
23. ENGINE COMPARTMENT: Rear of engine (bellhousing flange) must
be mounted at least 72 inches forward from centerline of rear axle.
Engine offset must be kept within two inches of centerline of front
crossmember with engine level. Minimum 11 inch engine height from
ground to center of crankshaft. Radiator must be mounted in front
Cooling system may be modified. Overflow tubes must be directed
to ground between frame rails. No vacuum pumps.
24. ENGINE SPECIFICATIONS: All cars utilizing a GM604 crate engine
must clearly display on both front roof posts the word CRATE. Must
be contrasting in color from body, minimum two inches tall. Markers
(A) CRATE ENGINE: Must use unaltered sealed GM #88958604 or #19318604
crate engine with additional IMCA Cable-Lok system – NO EXCEPTIONS.
Upon inspection, any different, altered or missing GM seal bolts
or IMCA Cable-Loks will result in disqualification, loss of all
IMCA points for the season, $5,000 fine and a 30-day suspension
from all IMCA-sanctioned events. GM seal bolt exception is IMCA
approved and issued Cable-Lok repair system, oil pan may be replaced
by IMCA certified repair center with
Champ pan #CP100LTRB and Champ pick-up #100SB. $250 fine for any
crate engine not using required pushrods, valve springs or rocker
arms. $250 fine for utilizing altered rev-limiter components. Any
driver using crate engine cannot claim engine or have engine claimed.
During same season, no driver is allowed to claim an engine after
competing with a crate. If a driver switches to a crate after claiming
an engine, the crate engine is then claimable.
(B) CLAIM ENGINE: Any American make steel engine block allowed.
Aftermarket and OEM performance blocks allowed. Cast iron or aluminum
intake manifolds only. Steel cylinder heads and oil pan only. Flat
tappet cam/lifters and stud-mounted rocker arms only. Magnetic steel
retainers only. No shaft, pedestal, or offset rocker arms, titanium
engine components, stud girdles or mushroom lifters. Lifter diameter
and configuration must match OEM passenger block. OEM firing order
cannot be changed (GM: 1-8-4-3-6-5-7-2).
All engines must be able to be used in conventional passenger car
without alterations. Engine mounts cannot be removed or altered.
Castings and fittings must not be changed.
No machine work on outside of engine (no lightweight engine blocks).
All belt driven accessories must be on front of engine. ‘Wet’
sump oiling system only. External oil pumps go with engine if claimed.
25. ENGINE CLAIMING RULES: Refer to www.imca.com for claim eligibility
(A) $1,050 cash, or $100 and exchange, claim on engine, flywheel
and balancing plates ($25 goes to wrecker and $25 to official for
each engine). Claimed driver has option of accepting cash, or exchanging
engines with claiming driver.
(B) Claim does not include - 1. clutch, 2. pressure plate, 3.
bellhousing, 4. headers, 5. carburetor, 6. starter, 7. motor mounts,
8. oil/temp. sending units, 9. carburetor spacer, 10. fan and pulleys,
11. clutch ball, 12. clutch arm, 13. throw out bearing, 14. dip
stick, 15. water pump, 16. fuel pump, rod and plate, 17. distributor,
18. plug wires, 19. water outlet and restrictor, 20. breathers.
26. POINT STRUCTURE/PROCEDURES: Refer to www.imca.com for automatic
27. EIRI: (Except in rare instances) Decisions of IMCA Officials
are final and binding without exception. In some cases, track safety
rules may take precedence over IMCA rules - any discrepancy between
IMCA and track rules should be brought to the attention of IMCA.
Any rule changes or clarifications during the course of the year
will be amended at www.imca.com as well as published in Inside IMCA,
the official newsletter of IMCA, and will be considered as an official
part of these rules.