2008 Modified Rules and Specifications
IF IT
DOESN’T SAY YOU CAN DO IT,
THEN YOU CAN’T.
1. Safety Equipment: Rules apply at all times
car is on track. Snell-rated SA95 or SA 2000 helmet required.
Roll bar padding required in compartment. SFI-approved full fire
suit, fire retardant neck brace, gloves and shoes required. Head
and neck restraints; collapsible steering shaft. Driver-side
window net required minimum 16” x 20” ribbon or mesh style and
must be mounted so latch is at top front of window, or arm
restraints. Minimum three-inch wide five point safety belt
assembly required, must be mounted securely to roll cage,
recommended to be no more than one year old. Kill switch
required within easy reach of driver and must be clearly marked
“off” and “on”.
2. Frame: OEM complete, 1964 or
newer, American rear wheel drive passenger car frame only. No
sports car frames. Frame must be full and complete, cannot be
widened or narrowed, and must be able to support roll cage on
both sides, except: 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; front cross member 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 four-inch tall frame stiffener may be welded
directly to outside of left side frame rail. Minimum wheelbase
108 inches, maximum 112 inches, both sides. No part of frame can
be lower than four inches from ground except front cross member.
3. Roll Cage: Must consist of continuous
hoops, minimum 1.75-inch O.D. tubing, with a minimum wall
thickness of .095-inch for main cage, frame-mounted in at least
six places, low carbon or mild steel recommended. Must consist
of a configuration of front, rear and top hoops connected by
tubing on sides or side hoops. Drivers 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 l.5 inch O.D. and .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 l.25 inch O.D. and .083-inch wall
thickness, and one top door bar, minimum l.5 inch O.D. and
.083-inch wall thickness. Steel door plate, 18 gauge or
.049-inch minimum thickness, must be securely welded to outside
of door bars and cover area from top door bar to bottom door bar
and from rear hoop down-post 5-inches in front of seat. Must be
visible for inspection.
5. Body: Body may extend no
more than 2" beyond outside of rear tire. Must be same width, front to rear,
and parallel to OEM frame. Engine compartment must remain open
(no side panels). Hood must be enclosed at rear. No panel in
front of right door to engine compartment. No inner panels. No
car covers. Must have front windshield and rear window support
posts. Driver and passenger side windows must have at least
12-inch opening, measured at center of window, between lowest
point at top of window, whether interior or body. May use Lexan
in sail panels. May use full windshield. Must be fiberglass or
metal full size roof, rounded in all directions. Maximum 4-inch
plastic skirting allowed on bottom of doors and quarters. No
reflective doors or quarter panels. Outside of tires must be
widest part of car. Spoilers max 8” tall.
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 further
back than steering wheel. Minimum .125-inch aluminum, or
.060-inch steel, complete floor pan required. Aluminum high-back
seat only and must be bolted in 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. Acculators cannot be mounted between
driver and left-side door bars. No devices that would enable
driver adjustment to alter wheelbase or for weight, jacking
while car is in competition. No mirrors or reflective sun
visors.
7. Front Suspensions: All components must be
steel, unaltered OEM, in OEM location, and replaceable by OEM
parts, except: Tube-type upper A-frames with aluminum/steel
cross shaft, and mounts can be moved; OEM replacement lower
A-frames. Rubber, nylon or steel lower A-frame bushings, no
offset or bearing type; welded or bolted shock mount on lower
A-frame. Lower A-frame mounts and bolt holes on frame must be in
OEM location. OEM ball joints only. Sway bar must be unaltered
OEM.
8. Steering: All components must be steel,
unaltered OEM, in OEM location, except: outer tie rod end and
adjustment sleeve may be required by a minimum .625-inch steel
rod end and steel tube: spindles can be ground for brake caliper
clearance only; unaltered, OEM replacement Pinto spindles must
be right and left, and of same design; bolt on spindle savers
allowed; steel steering shafts and knuckles only; steering quickner, steering wheel and quick release may be aluminum:
cockpit steering may be modified, must be kept on left side. No
rack and pinion.
9. Shocks: One steel, non-adjustable,
unaltered shock per wheel. One additional shock allowed on rear
suspension. No bumpers or stops. No threaded body, front
coil-over, air, or remote reservoir shocks. No Schrader valves.
Front half may be shielded.
10. Springs: One coil and/or leaf spring per
wheel only. One additional spring allowed on pull bar or lift
bar, may be progressive. Any coil spring. No torsion bars or air
bags.
11. Rear Suspension: All components must be
steel. No covers allowed. Rear of frame may be altered to accept
leaf or coil springs. Steel coil-over eliminators or steel/
maximum coil-over kits allowed -- must conform to shock and
spring rules. One mechanical traction bar (pull or lift, not
both) spring size optional. Rubber bumpers allowed only on pan
hard bar and mechanical traction bar. No sway bar. Chains may be
used on rear suspension.
12. Rear End: Any steel approved O.E.M.
passenger car or truck rear end allowed.
May run Quick Change rear
end.
Safety hubs (floater)
allowed. All components must be steel, except lowering blocks,
axle cap and drive flange. Inspection hole in housing is
required. Full steel spool, steel mini spool or welded rear ends
only. Steel axles only. No quick change devices or cambered rear
ends. One piece drive flange only. No torque dividing
differentials. No scalloped ring gears.
13. Bumpers/Rub Rails: Steel only. Bumpers
must be used both front and rear at all times and welded, or
mounted with minimum 1.25 inch O.D. tubing. 065 wall thickness
on front - .095 wall thickness on rear. Two bar front bumpers
must be 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. Rear bumper and nerf
bars can be no wider than tires.
14. Tires/Wheels: Asphalt
pull offs OK must stay on 8" rim. Must tech 45 min duro. 8 inch wheels only. IMCA
type tire American Racer or Hoosier (asphalt) or 8” Southwest
speed racing tire. 60 compound. Must be no softer than 45
degrees durometer after a feature with no cool down period.
Grooving and siping ok. Alum. Or steel spacers only. (right rear
bead lock only) Rim mounted bleeder valves ok.
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, min. 0.810-inch thickness. Vented rotors
only, no scalloped rotors. No brake shut-off or pressure
sensitive devices. One proportioning device allowed, front to
rear only. Brake lines must be visible.
16. Exhaust: Round tube headers only. All
primary header tubes must enter directly into one collector, at
same point at end of header. Must be no louder than 95 d.b.
Mufflers mandatory. All exhaust must go thru mufflers. Two per
car, one per header. No exhaust sensors.
17. Fuel System: Mechanical or belt driven
fuel pump only and must be mounted at front of engine
(optional). Racing fuel cell required, maximum 32-gallon
capacity, must be in minimum 18-gauge steel container. Cell must
be securely mounted behind rear axle, between rear tires,
minimum of four inches ahead of bumper, minimum of ten inches
above ground. Must mount with minimum two .125-inch thick solid
steel straps, two inches wide around entire cell. All cell
mounts must be steel, securely welded to frame cage. Protective
tubing must cover 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.
Pick-up must be on top or right side of cell. Limit of one fuel
filter. No cool cans. No top flow air cleaner housings. One
naturally aspirated 2- or 4- barrel carburetor only. No
adjustable carb spacers.
18. Fuel: Gasoline or alcohol. NO
performance-enhancing additives. Upper cylinder tube allowed.
Fuel sample may be taken from any car at any time.
19. Weight:
No weights and/or loose objects in driver compartment. Weights
must be securely mounted to frame or roll cage and painted white
with car number on it. Must be attached with a t least two
.5-inch bolts. No titanium, magnesium or carbon fiber products.
No gun-drilled, tubular, hollow bolts or studs. Steel fasteners
only.
20. Battery/Starter. One 12-volt battery only,
must be shielded and securely mounted between frame rails. Must
have capability of starting without being pushed or pulled. 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 transmitting or
listening devices, timing retard controls, or digital gauges
(including tach). No electronic monitoring computer devices
capable of storing or transmitting information except analog
tach. No adjustable ignition control boxes. Only one 12-volt
ignition box allowed, must be out of driver’s reach. No
additional ignition accessories allowed. Only change allowed to
ignition box is one high-end rev-limiter setting. This setting
can be changed through one chip only, or an internal setting
inside box. No electronic traction control devices
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 approved after-market transmissions allowed --
two-speed, three-speed, four-speed and automatic. No five speed
(or more) transmissions. No in and out boxes or quick change
devices allowed. Functioning shaft levers must be in OEM
location on all OEM production type transmissions. Berts and
Brinns OK. Flexplates must be full, steel, unaltered OEM, or OEM
replacement. Flywheel/flex plate must bolt to engine between
clutch assembly and crankshaft and all driveline components
within bell housing must rotate while car is any gear.
Transmission must be one of the following designs: Manual: Must
have a standard OEM case and working disc-type clutch or
approved cone or disc-type coupler inside an explosion-proof
steel bell housing. 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 aluminum. Bell housing can have only a hole
for throw out bearing lever of hose, must be 270 degrees around
top of clutch and flywheel area. Standard or reverse mount
starter allowed, must directly engage flywheel. Automatic: Must
remain in OEM or OEM replacement case, with a functioning OEM
appearing pump. Must have approved scatter shield. Scatter
shield must be constructed of minimum of .125-inch by three-inch
steel, 270 degrees around flex plate. Aftermarket: Must be
approved, aluminum case, with internal clutch. Must bolt to
explosion-proof steel bell housing, and use full, steel,
unaltered OEM or OEM replacement flex plate with starter mounted
in OEM location. Drive Shaft: Minimum two-inch diameter steel
drive shaft and must be painted white. Steel slip-yokes only.
360-degree drive shaft loop required and must be constructed of
at least .25-inch by two-inch steel, or one-inch tubing, mounted
six inches back from front U-joint.
23. Engine Compartment: Rear of engine (bell
housing flange) must be mounted at least 72 inches forward from
centerline of rear axle. Engine offset must be kept within
2-inches of centerline of front cross member with engine level.
Minimum 11-inch engine height from ground to center of
crankshaft. Radiator must be mounted in front of engine.
Overflow tubes must be directed to ground between frame rails.
24. Engine Specifications: Any American make
engine allowed. Steel heads, blocks and oil pan only. OEM block
only, except no GM Bowtie, Ford SVO or Chrysler W-2 blocks. No
mushroom lifters, cannot alter lifter bores. 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. “Wet” oiling system only. Aluminum heads okay
but must bolt 40 lbs. In front of motor plate.