EXTREME PRO STOCK Class Rules
Extreme Pro Stock or XPS followed by the car
number. Numbers must be at least 4” tall and on both side
windows, upper left of rear window and upper right of
FIELD: 8 car qualified field. If
13 or more cars enter, it will be a 16
car field and purse adjusted.
Decals Required on both sides of the
vehicle, front fender or hood scoop.
PDRA Logo required on both sides of
Minimum weight at conclusion of run, including driver 2,400
lbs with a Lenco Transmission
Minimum weight at conclusion of run, including driver 2,435
lbs with a Liberty Transmission
All rules subject to change at the sole discretion of the PDRA
Technical Services Department.
Alternates receive ONLY 25 entry
REQUIREMENTS AND SPECIFICATIONS
APPEARANCE: All vehicles must be professionally finished,
painted, lettered, numbered and decaled.
BELLY PAN: Required. Must extend beyond leading edge of engine
and accessories and incorporate a 2 inch vertical lip on the
front edge of all units.
BODY: Must be 2000 or later model year factory produced 2 door
coupes and sedans. Sports cars, sedan deliveries and trucks
prohibited. Original OEM body shell or PDRA accepted composite
replacement required. Chopping, channeling, sectioning, or
other alterations to contour, length or width are prohibited.
All composite replacement parts must be PDRA accepted and
exact duplicates of OEM components and may not be modified.
The front end may be lengthened in the cowl area to facilitate
body relocation and wheelbase modifications. The maximum
front- end overhang on all entries is 45 inches.
BUMPERS: Stock or composite duplicates required front and
rear, may be molded into body. Must be original size and
DOORS: Must be functional from inside and outside. Exact
duplicates in fiberglass or carbon fiber permitted. All
entries must incorporate a metal deflector between the fenders
and the leading edge of the doors.
FIREWALL: Moving stock firewall rearward for engine
installation permitted. Replacing stock unit with one of .024”
steel or .032” aluminum allowed; Magnesium prohibited.
FLOOR: Replacing stock floors with .024” steel or .032”
aluminum allowed. Replaced floors must be stock in appearance
and location. Driver’s side floor pan must be steel and must
extend from firewall to rear of driver’s seat and must be
welded in place. Chassis, frame and drive line must be below
floor. Rear floor may not be higher than 8” above door sill.
Belly pan mandatory between the center frame rails extending
from the rear to the front cross member or to the bell
housing. All pans must be designed to facilitate fluid
retention. If belly pan is utilized, the drip pan or secondary
oil retention blanket is not required.
GRILLE: Must be full stock production for body used and
visible from front. May have covering over back of grille to
prevent air passage. Any factory accessory package must be
accepted by PDRA, i.e., spoilers, air dams, etc.
HOOD AND HOOD SCOOP: One opening only. The highest point of
the hood scoop may not exceed 15” in overall height above the
original hood surface, measured from the leading edge of the
scoop. Must be finished and painted to follow body paint
scheme. Hood must be stock size with no bubbles. Cowl section
may be molded to hood. A minimum of four fasteners must be
used on the leading edge of all lift-off hoods. Sensors,
lines, or wires, etc. are prohibited from being in hood scoop.
STREET EQUIPMENT: Complete stock seal beam head light lenses
or accepted replica and stock tail light lenses in original
factory location required. Any other street equipment which
does not affect external appearance may be removed. Side
marker lights optional. Operational tail light required and
must be controlled from the driver’s compartment.
SPOILERS: Rear spoilers must measure between 14” to 17”,
measured from the body line at spoiler transition point to the
tip and may have no less than 0 degrees from horizontal. May
not be molded into deck lid. All spoilers to be painted to
match paint scheme. Rear of chute pack cannot be forward of
rear tip of spoiler. Roof-mounted spoilers prohibited. Air
foils prohibited. Any front spoiler used must have been
factory available for body used. Spoiler outside of deck lid
opening may not exceed 8” wide. Spill plates may be no more
than 6” high and 26” long. Spill plate may not be molded to
the quarter panel. A straight edge will be placed on the
spoiler, perpendicular to the centerline of the car and level
to the ground. Distance between level and lowest part of
spoiler can be no more than 2”. A wicker bill must be attached
across the entire trailing edge of the spoiler. It must be
constructed and attached in a way that will prevent air from
passing under or through the unit. It must be 90 degrees from
top of horizontal plane and a minimum of 1/4” high and a
maximum of 1/2” high.
WHEEL WELLS: Rear, must be separate for each tire.
WINDSHIELD AND WINDOWS: Full windows required, .125
polycarbonate materials, such as Lexan MR 4000, allowed. Must
match original contour and shape, and mount in stock location.
No bubbles in side windows for tire clearance. Windows must be
closed, need not be operative. Cutting and/or notching
windshield permitted if covered by hood scoop.
BATTERY: Maximum 2 batteries. Must be securely fastened. Must
have external master electrical shutoff marked “push-off”.
BALLAST: 250 lbs maximum. Shot bags must be contained in
weight box. Ballast attached on or in front of the forward
cross member is limited to 40 lbs maximum, including bracket.
The bracket may not exceed 12” in length, measured from the
cross member, attached with a minimum of (4) 1/2” bolts. The
maximum distance from the front of the bracket to the front of
the motor plate is 36”. Any car found with unsecured or
illegal ballast following a run will be disqualified from the
event at discretion of the PDRA Technical Services Department.
BRAKES: Four wheel brakes mandatory with dual master cylinder
mounted above frame rails on all entries. Steel brake lines
CHASSIS: SFI 25.1 E certification required. When an event is
contested at a NHRA Member track, only PDRA or NHRA chassis
certification will be permitted.
DRIVER: Must be in stock location. Driver’s seat to be no less
than 24” from center of rear axle to seat back (where shoulder
harness passes through).
ENGINE SETBACK: Maximum setback is 80.125” as measured from
the center of the rear axle to the back of the engine block.
Modifications to the block that would permit additional
setback are prohibited.
FUEL SYSTEM: One SFI 28.1 front-mounted fuel cell mandatory,
with pressure cap be vented outside of body. Trunk mounted
fuel system prohibited. Fuel circulating systems that are not
part of the fuel system are prohibited. All fuel cells must be
mounted between frame rails and protected by 1-1/4” x .065
GROUND CLEARANCE: Minimum 3” from front of car to 12” behind
centerline of front axle, 2” for remainder of car.
RADIATOR: Full size automotive radiator in front location with
one water pump mandatory. Remote mounted water pump permitted.
STEERING: Stock-type steering in conventional location
required. Minimum steering wheel outside diameter is 12”. SFI
42.1 disconnect is mandatory.
SUSPENSION: Full automobile production systems required.
Minimum, one hydraulic shock absorber per wheel. Fabricated
units permitted. Lightening of stock components prohibited.
Rigid mounted suspensions or straight front axles prohibited.
TIRES: Slicks permitted. Must be automotive type designed for
racing. All tires must have manufacturer, model and size
information clearly designated if used in competition.
Clearance from outside of front tire to inside of fender at
widest point not to exceed 4”. Rear clearance 3” from outside
of tire to inset of fender at widest point. Inner liners
No Radial Tires allowed.
WHEELS: SFI 15.1 bead-lock rear wheels mandatory. Maximum
WHEELBASE: Minimum 100, Maximum 105. Maximum variation is
1” side to side.
WHEELIE BARS: Required. Non-metallic wheels required. Maximum
length of wheelie bar 80” from center of housing to center of
wheelie bar wheel.
CLUTCH: SFI Spec 1.2 Clutch Assembly required. Release bearing
engagement/disengagement must be manually operated by the
driver's foot. The use of electronics, pneumatics, hydraulics,
or any other device is prohibited from affecting clutch
operation. Lock up units prohibited as all clutch levers must
attached to the pressure ring. Clutch assembly must be
contained in an SFI 6.1 or 6.3 bellhousing.
DRIVELINE: Full 360 degree drive shaft tube required over
yoke, extended from transmission tail shaft a minimum length
of 12” required from transmission tail shaft. Minimum
thickness of tube housing is .050” chromemoly or titanium. Two
piece accepted with minimum 6 3/8” grade 8 bolts.
FLYWHEEL SHIELD: SFI 6.1 or 6.3 with current certification.
See SFI 6.1 or 6.3 for motor plate requirements.
REAR END: Automotive type required. After market axles
required with 5/8” stud bolts and axle retention device.
Welded spider gears prohibited. Full floating or live axle
assembly is optional.
permitted (Lenco or Liberty).
Automated shifters and electronic timed shifters
are prohibited. Multi-functional single button shifters
prohibited. If a pneumatic shifter is used, each shift must be
activated by its own individual control button. Routing of
pneumatic shifter lines must be PDRA accepted prior to
competition. All pneumatic shifter lines act independently and
not a result of or activate other air or electric systems on
the entry. Torque converter equipped automatic transmissions
CARBURETION: Limited to any two 4-bbl. American automotive
carburetors available to the general public with any internal
modifications. Carburetors may be split.
CYLINDER HEADS: Cylinder heads must be configured after OEM or
PDRA accepted pattern, contain OEM or after market factory
casting number & logo, and must be available to the general
public. Heads must be aluminum or cast iron. No billet
materials, magnesium or other materials allowed. Maximum 2
valves, and one spark plug per cylinder.
ELECTRONIC FUEL INJECTION: Permitted. EFI controller
manufacturer, model, firmware and software must be approved
for use by the PDRA Technical Services Department and must be
commercially available to all competitors prior to use in
competition. Maximum of 16 injectors placed in any location
above the cylinder head. EFI controller must operate in an
open loop configuration with no connection to oxygen sensor or
EGT sensor. EFI controller is stand alone, fuel only with rpm
signal provided from crank and or distributor trigger separate
from the ignition trigger. EFI controller can have output to
data logger only. Wiring harness cannot contain provisions for
oxygen sensors and must have specific part number approved by
the PDRA Technical Services Department prior to use in
competition. EFI controller can only send data to data logger
not receive. EFI controller cannot monitor any performance
criteria of the vehicle including acceleration, drive shaft,
wheel speed, track position, etc. The only sensors to be
utilized and or monitored with the EFI controller are coolant
temperature, fuel pressure, IAT (Inlet Air Temperature), MAP
(Manifold Air Pressure) and TPS (Throttle Position Sensor).
Competitors may utilize either 2-4 blade or 4-2 blade throttle
bodies. Throttle bodies must be installed with throttle blades
in a horizontal location. Forward facing throttle bodies are
not permitted. Throttle bodies must be production units
commercially available to all competitors prior to use in
competition. Intake manifold must be of conventional design
with no active components, i.e., runners. Inlet air must be
drawn from a single opening, forward facing hood scoop of
conventional design. EFI and carburetion cannot be combined on
an intake manifold.
ENGINE: Internal combustion, reciprocating, naturally
aspirated, single camshaft, 90 degree V-8 automotive-type
mandatory. Crankshaft centerline must intersect cylinder bore
centerlines and be symmetrical. Limited to
833ci hemi and
843 ci on wedge entries, no tolerance. Blocks may be aluminum or
cast iron. No magnesium or other materials allowed. One
distributor maximum. Maximum 5” bore spacing. Every engine
must have an individual Serial No. given by engine builder.
The Serial No. must be located in a clearly visible place on
the cylinder heads and block. All moving engine components
must be accepted prior to utilization. Additionally, the use
of beryllium, carbon fiber/kevlar, ceramic, or composites are
prohibited from use on these components. The rod and main
bearing assemblies must be of conventional sleeve design.
EXHAUST: Open exhaust with headers mandatory. Side exit
exhaust systems prohibited. All removable
multi-piece exhaust collectors/stacks must be securely
fastened with either an NHRA-accepted header tether, a minimum
½” (half-inch) stitch weld located on each primary tube or be
permanently attached to the vehicle body or frame with
positive fasteners (i.e. exhaust hangers, support brackets,
bolts/nuts, etc.) such that they require tools for removal.
FUEL: All entries must utilize VP Racing’s Q16 or C23 Fuels.
The use of propylene oxide, nitrous oxide, methanol,
nitromethane, or any other additive is prohibited.
IGNITION: After market electronic ignition boxes may not be
modified from factory specifications. . If digital ignition
system has internal programmable retard functions, all of the
external wires that have the ability to activate similar
functions must be clearly disconnected and removed from the
wiring harness. (Ex. MSD 7530, 7530T and75301 (pink, tan,
violet and white wires). MSD 7730 power grid system allowed
provided the MSD 7720 (Ignition Module), MSD 7740 (4 connector
CAN-Bus Hub) and /or MSD 7751 (Launch Control Module) are the
only products used to complete the ignition system. The 5
individual step retard wires (pink, violet, tan, light green
and green) must be clearly disconnected. Any electronic
traction control device prohibited.
OIL LINES: All oil pressure lines must pass a minimum pressure
test and be clearly labeled as passing the testing process.
CREDENTIALS: A valid competition license is required. A valid
NHRA or IHRA competition license will be accepted and may be
transferred when presented with a current physical. When an event is
contest at an NHRA Member track only PDRA or NHRA competition
licenses will be accepted.
DATA AND ELECTRONICS ACQUISITION: Allowed.
TOW VEHICLES: Allowed. A valid driver’s license is required to
operate any type of tow vehicle. All passengers must be seated
inside of vehicle with all doors closed. Riding in open
hatchback, trunk or cargo area not allowed. ATV’s are allowed
with a maximum of one passenger who must be seated at all
times. Golf carts are allowed with a maximum of four
passengers who must be seated at all times. Posted pit speeds
must be obeyed at all times. If pit speed is not posted,
maximum pit speed will be 5 mph.
DRIVER RESTRAINT SYSTEM: SFI 16.1 certification required (7
point system recommended).
ENGINE CONTAINMENT SYSTEM: SFI 7.1 lower engine containment
system required. If a flexible 7.1 system is utilized, it must
be accompanied by a carbon fiber or aluminum belly pan with a
minimum 2” vertical lip.
FIRE SYSTEM: SFI 17.1 system required. System must contain a
minimum of 5 lbs of fluid or gas fire suppression agent. One
nozzle required inside driver’s compartment must be directed
at driver’s feet. Two or more nozzles must be directed at
front of engine and fuel cell.
HEAD AND NECK RESTRAINT: SFI 38.1 required. An aluminum skid
plate located above driver’s head is recommended.
HELMET: SN-2010 or newer, SFI 31.2 or 41.2 required. Use of
open face helmet prohibited. Eject Helmet Removal System (Part
# SDR 890-01-30) or equivalent required.
MASTER ELECTRICAL CUTOFF: Required. Must be clearly labeled
PARACHUTES: Dual parachutes required. Separate shroud-line
mounting points with 1/2” sleeved grade 8 bolts required.
PROTECTIVE CLOTHING: A driver’s suit meeting SFI Spec.
3.2A/15, gloves meeting SFI 3.3/5 and shoes meeting SFI 3.3/5.
RF SHUTDOWN RECEIVER: Properly functioning Electrimotion
shutoff device (part numbers SB001 and RF001) recommended.
ROLL BAR PADDING: SFI 45.1 required.
UPHOLSTERY: All seats must have minimum 24 inch high seat
backs. Seat frame of chromoly tubing must be installed as a
permanent part of the chassis. “Wrap around” type seat or
fiberglass one-piece bucket accepted. Dash board exterior
appearance must be retained: replicas of original allowed.
Head liner optional; area must be painted if headliner is not
used. Driver’s seat foamed with energy absorbing material,
formed for the driver and covered with flame retardant
material is required. Lateral helmet supports required.
WINDOW NET: SFI 27.1 required.
BE SURE TO ALSO VIEW OUR "OVERALL / GENERAL SERIES RULES"