2018 DIAMOND PARK SPEEDWAY OPEN WHEEL
‘‘RACE RECEIVERS MANDATORY”
RULES & SPECIFICATIONS
5" spoiler. 8000
RPM chip. 2,350# after the race with the driver (whether steel or
alum. head). See body and frame diagrams at
ARTICLE 4: BODY
4.1 1970 or
newer American compact passenger car only. Panel vans or station
wagons are not allowed.
4.2 An aluminum
half-windshield may be used on driver’s side of the front window
appearing front window support units must be used (painted roll bars
are not acceptable substitutes). Front window may have a support of
no more than twenty (20) inches at bottom, going straight up to top.
4.4 A minimum
window opening of twelve (12) inches must be maintained on all four
(front, back, left and right) window openings.
at top of windshield is not allowed. Bodies must have standard
appearing windshield opening and corner post must follow standard
roof line of vehicle must be maintained with a maximum of five (5)
inches of slope from rear to front. Two (2) inch maximum roll,
turned downward, is permitted along the front edge of the roof. No
more than one-half (0.5) inch stiffener allowed at the rear of the
roof and must turn down perpendicular to the ground. A maximum of
one (1) inch roof lips allowed on the left and right edges of the
roof. A maximum of four (4) inch sides on roof allowed. OEM Gremlin
roofs are not allowed. Aluminum roofs are permitted but must remain
flat and not concaved.
4.7 Sail panels
must be of matching design with matching styles on both sides of
racecar. Sail panels may have a maximum bow of four (4) inches top
to bottom, maximum bow of three (3) inches front to back and may be
no more than eight (8) inches above the back edge of deck.
4.8 Reverse hood
rake is not allowed. Hood must be level or slope forward toward nose
of racecar. Back of hood may be no more than two (2) inches above
decking and sealed off completely. Lips on the sides of hood are not
4.9 Belly pans
are not allowed. A belly pan will be defined as any object or
material that alters the airflow under the racecar. A rock shield
may be installed to protect the oil pan and the bottom of the motor,
from the front cross member no further back than the rear engine
mount (mid-plate/mid-mount) no wider than the radiator front to
(engine covers) in front of the door next to the engine compartment
are permitted, but must maintain a six (6) inch gap from the door.
One side must remain open for inspection of engine on the scales.
4.11 Bodies with
excessive damage (as determined by an official) will not be allowed
width of the racecar may not exceed 78 inches. Width shall be
measured from the widest points on each side of the racecar.
4.13 The rear
deck lid and/or trunk area must be covered.
overall nose width is forty-two (42) inches. Two (2) inch nose fins
are permitted along both sides of the nose. Nose fins may not pass
the leading edge of radiator or continue past leading edge of hood.
All aluminum of the nose (including the fins) must be completely
inside the outer edges of the bumper. Nose fins must match side to
side. If it is between nose fins, it is the nose; if it separates
from the hood, it is the nose.
valances and/or plastic nose pieces are permitted but no plastic may
extend in front of the bumper. Plastic may flare past the sides of
the bumper. Aluminum or steel is not allowed outside the bumper.
4.14.3 All nose
piece components must be a minimum of five (5) inches above the
door and quarter panel height permitted is thirty-seven (37) inches
total material. Doors and quarter panels may be mounted a maximum of
one (1) inch above the deck, and must match side to side –NO
TOLERANCE. A maximum five (5) inch plastic skirt on bottom of doors
and quarter panels and nose piece is permitted.
hood and nosepiece, the top of the body should extend no further
forward than the back of the engine block. The bottom of the body
may extend up to eight (8) inches forward of the back of the engine
4.17 A maximum
five (5) inch plastic skirt on bottom of doors and quarter panels
and nose piece is permitted.
spoilers shall be measured as complete material height including
hinge and all hardware associated with connecting the spoiler to the
decking. a. Option 1: Five (5) Inch Spoiler – includes USMTS/USRA
spec engine, 23-degree steel-headed flat tappet engine and GM CT525
crate engine. The maximum rear spoiler height shall be five (5)
inches. b. Option 2: Six (6) Inch Spoiler – includes USMTS/USRA
concept engine or GM #88958604 or #19318604 crate engine (GM 604).
The maximum rear spoiler height shall be six (6) inches. c. Option
3: Three (3) Inch Spoiler – includes open engine. The maximum rear
spoiler height shall be three (3) inches.
spoiler may not exceed the width of the rear deck lid, must be flush
to the deck and must extend from right edge of deck to left edge of
deck. Spoiler must remain flat.
spoiler must remain separate from sail panels.
4.17.4 A maximum
of two (2) center supports and a maximum of two (2) side supports
may be attached to the front of the rear spoiler (see body diagram
wings, lips, deflectors or other air spoilers (except as noted
above) are not allowed.
4.17.6 Any fins,
wings, lips, deflectors or other permitted air spoilers must match
corresponding part on opposite side of racecar.
4.18.1 Center of
bumpers (front and rear) must be a minimum sixteen (16) inches and a
maximum twenty (20) inches from ground.
front and rear bumpers must be used, and may not have any sharp
edges. Any inappropriate bumper may be disallowed at the discretion
of an official. Front bumper should be mounted from frame end to
frame-end with the bottom loop parallel to ground. Bumpers must be
made of a minimum of one and one-quarter (1.25) inch tubing and must
be able to support the racecar if lifted by a tow vehicle. Top bar
must be directly above bottom bar.
bumpers may be constructed of tubing or flat stock, and must protect
the fuel cell. Rear bumpers may be no more than two (2) inches wider
than the body on each side and may not be openended (must wrap
around and be connected to side rail bars).
4.18.4 Nose may
not extend past front bumper and must be a minimum of five (5)
inches above the ground. Nose must be completely within the bumper.
bumper may be a maximum width of 44 inches from outside to outside.
Nose must be completely inside of bumper. Nose tin may have a
maximum width of 42 inches at bottom. Note: If it is between nose
fins, it is considered to be the nose; if it separates from the
hood, it is considered to be the nose.
racecars must be numbered with large legible numbers on both sides,
on top and on the nose and real panels. Numbers on the sides of the
racecar should be in contrasting color from the body and be at least
four (4) inches thick and at least eighteen (18) inches high. Top
numbers should be at least four (4) inches thick and twenty-four
(24) inches high.
reserve the right, in the public image of the sport and/or the USRA,
to assign, approve or disapprove any advertising, sponsorship or
similar agreement in connection with any event. All cars must be
neat appearing and are subject to approval of officials to compete.
By competing in an event, all drivers agree to comply with the
decisions of officials in this regard.
ARTICLE 5: ROLL CAGES
5.1 Round steel
tubing, seamless roll-over bars are required for the basic roll
cage, and must be acceptable to officials. Acceptable tubing is as
follows: minimum one and one-half (1.5) inches by ninetyfive one
thousandths (0.095) inch for mild steel and DOM tubing.
5.2 Roll bars
within the driver’s reach must be padded with an accepted material
as determined by an official. Fire retardant material is highly
and workmanship must be acceptable to officials. 5.4 Must be
frame-mounted in at least six (6) places.
5.5 Must consist
of a configuration of front and rear hoops connected by tubing on
the sides or side hoops.
5.6 With helmet
on and driver securely strapped into the racing seat, top of
driver’s head must not protrude above the roll cage.
5.7 Must have a
protective screen or bars in front window opening in front of
of driver’s feet utilizing a bar across the back of the engine with
vertical bars and rub rails or similar protection is mandatory.
5.9 Brace bars
forward of roll cage may not be higher than the stock hood height.
5.10 A minimum
of three (3) driver side door bars must be parallel to ground and
located perpendicular to the driver so as to provide maximum
protection for the driver, but without causing undue difficulty in
getting in or out of the racecar. Side bars must be welded to the
front and the rear of the roll cage members. Door bars and uprights
must be at least one and one-half (1.5) inches in diameter at a
minimum of eighty-three one-thousandths (0.083) of an inch thickness
and be gusseted in place. The door bars must have four (4) vertical
studs per side and must be equally spaced.
ARTICLE 6: FRAME
production complete full 1960 or newer parallel American passenger
car frames only. Frames may be cut in rear only at a point not
further than thirty-six (36) inches from center of rear end housing.
6.2 May only be
altered for the installation of springs and shocks.
components must be made of steel and be properly welded.
6.4 Must be full
and complete on both sides, may not be widened or narrowed and must
be able to support roll cage on both sides. All factory holes must
be present for inspection. All measurements must meet the frame
diagram tolerances listed or be within one-half (0.5) inch (either
way) of OEM measurements on any measurement not listed on frame
diagram – NO TOLERANCE.
height from ground is four (4) inches. Exception: front cross member
may be notched for radiator clearance only. Right front frame rail
must be a maximum of seven and one-quarter (7.25) inches above the
6.6 Jeep, Bronco
or similar four-wheel drive frames are not allowed. Sports car
frames are not allowed. Front-wheel-drives are not allowed.
6.7 Rear of
frame may be altered to accept leaf or coil springs.
ratchet or electric weight jacks are not allowed anywhere on the
racecar. Aluminum jack bolts are not allowed.
must be a minimum of one-hundred eight (108) inches on both sides
front clips are not allowed.
overall width of car (at front or rear) shall not exceed
seventy-eight (78) inches from outside of tread to outside of tread
– NO TOLERANCE. ARTICLE
7: COCKPIT, STEERING & SEAT
objects and/or weights are not allowed.
7.2 Air bags are
7.3 Rear view
mirrors are not allowed.
7.4 Floor and
firewall must be complete in the driver’s compartment. Minimum 0.125
inch aluminum, or 0.060 inch steel, complete floor pan required. No
interior sheet metal can be higher than or enclose a standard window
opening. Sheet metal in the driver’s compartment must be horizontal
from the top of the driver shaft tunnel to the right side door bars
or angle from the top of the drive shaft tunnel upwards to the top
of the right side door bars. Driver must be able to exit the racecar
from both sides.
7.5.1 Must be
OEM and remain within original bolt pattern for type of frame used.
Center link must match frame. Inner and outer tie rod end and
adjustment sleeve may be replaced with a heim end and steel tube.
7.5.2 Rack and
pinion is not allowed.
7.5.3 May be
modified to suit driver, but must remain on left side of cockpit (no
Quick-release metal coupling on steering wheel is mandatory. Plastic
couplings are not allowed.
Factory-manufactured racing seats are mandatory, and must be
acceptable to officials.
aluminum, plastic or fiberglass seats are not allowed.
7.6.3 Must be
properly installed and seat back cannot be moved back further than
rear edge of quarter post.
aluminum seats only. Full containment racing seats are strongly
ARTICLE 8: SUSPENSION
suspension must remain stock-type for the type of frame being used.
Steel aftermarket parts may be used as stock components as long as
they mount in the stock location and are the same size as the OEM
parts. This includes lower tubular A-frames. If using lower tubular
A-frames, must match factory specs. All parts must meet OE specs and
match side to side. GM 1978-1988 metric “G” body frames are
permitted to use the Nova lower “A” frames.
and/or titanium components are strictly forbidden. Magnet must stick
to all components.
tube-type upper A-frames are permitted and may be moved. Steel or
aluminum cross shafts are permitted.
springs are not allowed on the front. 8.5 Stock passenger car
spindles only. Fabricated spindles are not allowed. Bottom A-frames
may not be altered, lightened or moved and must match side to side.
8.6 Front sway
bars may be used. Front sway bars must be made of steel and may be
attached to the bottom A-frame using steel heim joints. Must be
solid full-length OEM.
8.7 Rear Suspension:
8.7.1 All rear
suspension radius rods and lift arms must be of a fixed solid steel
design. Hydraulic cylinders, torsion bars, bump rods, spring rods,
slider rods and/or shock-type radius rods to locate the rear end are
8.7.2 Radius rod
must be a minimum thirteen-sixteenths (0.8125) inch outside
diameter; may be round, hex or square shape; and must be a minimum
ninety-five one-thousandths (.095) inch steel thickness.
8.7.3 Only two
(2) radius rods per side are permitted. All rods must be of solid
design. Spring and/or trick type rods are not allowed. One
additional rod per side for brake floater only is allowed.
8.7.4 Axle Housing Mount (Birdcages)
a) Only one (1)
birdcage per side is permitted. Birdcage may consist of multiple
barrels but must bolt or be welded together to act as a single unit
containing both the top and bottom radius rod connectors.
b) All bearings
pertaining to birdcages must freely spin forward and backward.
c) Shock, radius
rods and spring must mount to birdcage. If one rod is floated, the
other rod must also be floated; If one rod is locked up, the other
rod must also be locked up (one bracket).
Swing arm type suspension where shock, spring or shock-spring
combination is connected directly to one of the radius rods.
2) Shock is
mounted solidly to rear end axle tube.
3) Spring is
mounted solidly to rear end axle tube In Exceptions 2 and 3, mounts
may be no more than seven (7) inches from center of axle tube to
center of lower heim of shock or slider with bracket welded or
securely bolted solid to axle tube.
additional floated birdcage-style bracket is permitted per side to
accommodate floated brake system only (one additional radius rod is
permitted to control this bracket).
pivoting and/or rotating mounts and/or brackets of any sort on the
birdcage are not allowed. All brackets or mounts must be welded or
bolted solid. Cleaves-style rotating mounts will be permitted on
birdcage only for mounting of shock and slider. 8.7.5 Only one (1)
mechanical traction device is permitted. Only one (1) pull bar or
one (1) lift arm is permitted. All other options are not allowed.
Covers of any sort in any relation to the lift arm or pull bar are
strictly forbidden. Rubber bushings and/or biscuits are permitted on
both lift arm and pull bar applications, but must be directly
connected and functioning in relation to corresponding part only.
pivoting and/or rotating mounts and/or brackets of any sort
(connected to and/or associated with the pull bar or lift arm) are
8.7.7 Lift arm
is defined as a solid steel triangulated bar that is connected at
the top (with one heim) and bottom (with one heim) of the rear end
housing, extending forward where it is connected to a shock (that
may utilize only the heim directly related to that one shock (ONE ON
EACH END), shock-spring coil over combination (that may utilize only
the heims directly related to that one shock (ONE ON EACH END)) and
a limiting chain (with or without a biscuit for cushion). One heim
only is permitted in this configuration. One stabilizer bar is
permitted to locate the front of the lift arm from left to right in
8.7.8 Pull bar
is defined as a continuous assembly (that may or may not contain a
spring or biscuit assembly located in-line to absorb torque) that is
connected to the top of the rear end with one heim and extends
forward to a solid mounting point located on the chassis where it is
connected with one heim. The mounting location at both the front and
rear of the pull bar may be adjustable but must remain constant
during competition (cannot be adjustable from the cockpit).
coil-over eliminators and/or steel-aluminum coil-over kits are
permitted on the rear only, but must conform to shock and spring
panhard bars are permitted, but must be made of steel and may be
attached by using a minimum three-quarter (0.75) inch i.d. steel
8.8.1 Any new
design of components pertaining to and/or containing shock
absorber(s) must be submitted to, and approved by, the USRA for
approval before these designs will be permitted for use in
competition. The manufacturer and/or competitor may be required to
disassemble any part or assembly for inspection before in-statement
of new part is permitted.
8.8.2 Only one
shock per wheel is permitted (five total). Shocks must be mounted
vertically and no more than twenty (20) degrees from vertical
(ninety (90) degrees) in any direction (only exception is fifth
shock may be mounted horizontally over pull bar). Dummy shocks in
relation to functioning shock absorbers are not allowed (i.e. no
dummy shocks to replace slider). Fifth shock is permitted only in
relation to pull bar or lift arm (example: 90/10 mounted in line
with the pull bar, this shock must run in same direction as the pull
bar, shock on lift arm must be mounted as referred to in the lift
arm summary in Rule 8.7.7). Shock may not be connected directly to
the pull bar in any way. 8.8.3 All shocks must be made of steel
(magnet must stick). Aluminum heims on shocks are not allowed (steel
conventional-type (closed on one end) shock absorbers are permitted.
Only single-shaft shocks are permitted.
8.8.5 Air shocks
and/or canister shocks are not allowed.
shocks, J-damper shocks, active mass damper shocks and/or
through-rod-designed shocks are not allowed.
8.8.7 Bump stops
(rubber and/or spring-type), spring rubbers or any other limiting
devices are not allowed on any suspension component including, but
not limited in relation to: shocks, springs, upper or lower “A”
frames (Exception; bump stops and/or various rubber biscuits are
permitted in conjunction with the pull bar or lift arm assemblies
only, limiting chains or blocks from rear-end housing to chassis,
and one (1) rubber bushing on front shock is allowed no more than
one-half (0.5) inch in total rubber thickness, plastic or steel
shims and or cups only.
Electronically-controlled and/or monitored shocks by any means or
methods is strictly forbidden. Cockpit adjustable shocks are not
shall be subject to claim, as outlined in Claim Procedures (Article
8.9.1 One spring
per wheel is permitted (five total). One additional spring is
permitted in the center of the car pertaining to the traction device
(i.e. spring on the pull bar or lift arm).
8.9.2 All coil
springs must be at least four and one-half (4.5) inches outside
diameter. Springs must be made of steel. Torsion bars in the rear
are not allowed.
Progressive, stacked and/or welded springs are not allowed.
wire diameter and coil spread must remain consistent from one end to
the other (Exception: last coil on each end may be closed and shaved
off to create flat surfaces for mounting).
conventional spring mounting devices are permitted. Widgets, trick
and/or spring-altering mounting devices are not allowed.
9.1.1 Must be
securely mounted inside frame rails and covered. If mounted outside
of frame rail, a nerf bar (minimum one and one-quarter (1.25)
outside diameter by ninety-three one hundredths (.093) thickness
tubing) must be installed around battery box for protection.
9.1.2 One (1)
12-volt or 16-volt battery is permitted. One (1) additional 9-volt
battery is permitted to run digital tachometer only.
converters are not allowed. 9.1.4 All battery posts must be securely
9.2.1 One (1)
unaltered ignition system is allowed (no secondary or back-up
systems). Recommended: MSD 6CT #PN6427.
Crank-triggered ignitions are permitted only on racecars utilizing a
GM CT525 crate engine. Must utilize MSD LS Series #PN6014CT set to
the GM recommended preset.
9.2.3 One (1)
coil only is permitted.
switch required within easy reach of the driver. The switch must be
clearly marked “OFF” and “ON”. Cameras pointing to any moving or
suspension parts are not allowed. Except for memory recall
tachometer, electronic monitoring computer devices capable of
storing and/or transmitting information are not allowed.
boxes shall be subject to claim, as outlined in Claim Procedures
utilize a maximum RPM rev-limiter for the following engine
combinations: 375 cubic inch displacement engines or larger is
7,800; 374 cubic inch displacement engines or smaller is 8,400;
USMTS/USRA concept engine is 8,000; CT525 crate engine is 7,300; GM
604 crate engine is 6,800. Revlimiter may not be within reach of the
driver while in cockpit and must be easily accessible to officials
at any time.
elements must be accessible for technical inspection. Any racecar
advancing spots and missing will be subject to disqualification.
pointing to any moving or suspension parts are not allowed.
ARTICLE 10: FUEL SYSTEM
10.1.1 Must be
automotive gasoline or alcohol only. Additives of any kind are not
allowed. E85 ethanol or racing fuel is permitted. Penalty for
illegal fuel is loss of points, cash and awards earned for that
10.1.2 May not
be blended with ethers or other oxygenates, and may not be blended
with aniline or its derivatives, nitro compounds or other nitro
containing compounds. Oxygenated fuel is not allowed.
fuel pumps are not allowed.
10.3.1 One (1)
two-barrel, four-barrel or Predator carburetor properly installed is
10.3.2 Must be
injection is not allowed.
adapter with gasket is permitted. Adapter and gasket combined may be
no more than two and one quarter (2.25) inches.
10.4 Fuel Cell:
10.4.1 Must be
commercially manufactured and must be mounted utilizing at least two
(2) steel straps. Straps must be two (2) inches wide at all
10.4.2 Must be
enclosed in a steel container and must be protected in rear of axle
by roll cage tubing mounted securely.
10.4.3 No part
may be lower than protective tubing. Protective tubing must be no
wider than six (6) inches on both sides. Fuel cell may be no lower
than ten (10) inches from the ground.
10.4.4 Must have
to a maximum capacity of thirty-two (32) gallons.
10.4.6 Must have
check valves. A ball-type, flapper or spring or filler rollover
valve is mandatory for fuel cells without a positive seal filler
ARTICLE 11: TIRES & WHEELS
11.1.1 Must be
fifteen (15) inches in diameter and eight (8) inches in width.
are not required.
11.1.3 Must be
reinforced steel only.
11.1.4 A steel
or aluminum bead lock may be used on the right front and right rear
wheels only, and may be mounted on the outside of the wheel so long
as it does not add over three-quarters (0.75) of an inch to the
overall width of the wheel.
mud caps are not allowed.
covers are permitted on right side wheels only. Inner mud plugs are
permitted. All mud covers must display car number on at least one
11.1.7 Wide five
wheel adaptors are not allowed.
11.1.8 Steel or
aluminum spacer between hub and wheel is permitted, but overall
width of racecar cannot exceed 78 inches (see Rule 4.19).
or steel lug nuts are permitted.
11.2.1 The only
tire permitted is the American Racer G60-15 KK704 (Short, Tall or
X-Tall). Tires should durometer 50 or harder after any race
is not allowed. Solvents of any kind are not allowed. Altering tires
with any components or chemicals which alter the manufacturer’s
baseline-settings of the tire is not allowed.
and/or siping is permitted.
sidewall markings must remain visible at all times. Buffing or
removing of the compound designations is not allowed.
ARTICLE 12: BRAKING SYSTEM
12.1 Must be
operating on all four wheels and must lock up all four wheels during
12.2 Must have
caliper and rotor on all four wheels. Vented rotors are required on
brake actuators are not allowed.
and/or pads may not be lightened and must be OEM
12.5 Steel or
aluminum single-piston OEM-type calipers are permitted. Piston
diameter must be the same on all calipers.
12.6 Rotors must
be steel and may not be lightened, scalloped or drilled but may be
slotted. Rotors may be re-drilled for different bolt patterns or
Front-to-rear brake bias is permitted (no left to right).
shut-offs are not allowed.
12.9 Brake lines
must be visible.
maintain minimum OEM dimensions for hubs, rotors and calipers.
ARTICLE 13: DRIVE SHAFT
13.1 A loop is
required and must be constructed of at least one-quarter (0.25) inch
by two (2) inch solid steel. Loop must be mounted no more than six
(6) inches from the front of the drive shaft tube. Alternatively,
two (2) loops of one-quarter (0.25) inch by one (1) inch solid steel
fastened to cross member are permitted.
13.2 Must be
painted white. Aluminum drive shafts are not allowed.
drive shafts are not allowed. Steel or carbon fiber drive shafts
only (carbon fiber may have aluminum yokes).
ARTICLE 14: TRANSMISSION
14.1 OEM three-,
four- and five-speed and automatic production-type transmissions are
permitted. Approved aftermarket transmissions are permitted.
14.2 “In and
out” boxes are not allowed.
14.3 Must all be
aftermarket transmissions are Bert, Brinn, Falcon, RaceGator and
Mitchell Machine Bullet Tranny with internal clutch.
14.5 Clutch must
be inside of bell housing for OEM production-type transmissions
(except as noted in Rule 14.4).
transmissions must be equipped with an explosion-proof steel bell
housing. Aluminum must be SFI-approved (Note: GM bell housing is not
and aftermarket transmissions must have a guard two-hundred seventy
(270) degrees around flex plate or flywheel, and must be constructed
of at least one-eighth (1/8) inch. Alternatively, automatic
transmissions may utilize an SFI-certified aftermarket guard. All
flex plates must be SFIcertified.
14.8 With engine
running and racecar in stationary position, driver must be able to
engage racecar in gear and then move forward and then backward at
time of inspection.
ARTICLE 15: REAR-END
passenger car or truck type is permitted. Aluminum is not allowed
except lowering blocks, axle cap and drive plate.
change rear-ends are permitted: Steel tubes only; ten (10) inch ring
gear only; pinion and carrier bearings must be tapered; titanium is
not allowed; wide-five wheel patterns are not allowed; aluminum
spools are permitted. Magnesium will be permitted until such date
that the cost increases, at which time only magnesium rear-ends
purchased prior to that date will be permitted and must have
original serial number.
rear-ends are not allowed. One-piece drive flange only.
devices are not allowed (includes Gold Track, True Track or similar
ARTICLE 16: ENGINE
16.1 General Engine Rules: Unless
otherwise noted, the following general engine rules apply to all
type shall determine the overall weight of the racecar (see Rule
17.3), spoiler height (see Rule 4.12.1) and RPM limits of the
rev-limiters (see Rule 9.2.5).
16.1.2 Must be
able to be used in conventional passenger car without alteration.
Motor mounts may not be removed or altered. Castings (includes
block, heads and intake) and fittings may not be changed. Machine
work on outside of engine, or on front or rear of camshaft, is not
allowed. If utilizing lightened blocks (removal of material from
inside and/or outside), an additional twenty-five (25) pounds of
weight must be added in front of the mid-plate.
sump” systems are not allowed. “Wet sump” oil system only. Internal
or external oil pumps are permitted; however, single pickup must
remain in pan with a maximum one (1) pickup and one (1) return line.
External remote oil tanks (dry sump tanks) are not allowed. Oil
coolers and remote filters are permitted.
Modification of cooling system is permitted. Radiators and oil
coolers may not protrude above interior.
American make may be used. Rear of engine (bell housing flange) must
be mounted at least seventy-two (72) inches forward from the center
line of the rear axle – NO TOLERANCE.
must be within two (2) inches of centerline of front cross member.
16.1.7 Must be a
minimum of eleven (11) inches from ground to front center of
blocks only –aluminum and/or titanium are not allowed.
tubes must be directed toward the ground and inside the frame rails.
must be mounted in front of engine.
system and/or mufflers must be mounted in such a way as to direct
spent gases away from the cockpit and away from areas of possible
fuel spillage. Mufflers may be required at track's discretion.
cams are permitted, unless otherwise noted.
manifolds must be made of cast iron or cast aluminum. External
modifications to cast aluminum intakes are not allowed. Internal
modifications are permitted.
headers are permitted, but cannot contain stainless steel. (Note:
Beginning January 1, 2018, TriY headers will not be allowed).
girdles and shaft rockers are permitted.
components must be of matching manufacturers (i.e. Chevy for Chevy).
may be angle milled, but valve angle must remain within one (1)
degree of original manufactured specification.
components must be of matching manufacturers (i.e. Chevy for Chevy).
drain back and cooling lines are permitted.
16.2 BRODIX Spec
Head Rules: Unless otherwise noted, the following BRODIX spec head
rules apply to both Engine Options #1 and Engine Option #2 below.
product numbers for the BRODIX aluminum spec head are SPCH
(Chevrolet), SPFO (Ford) and SPMO (Mopar) for USMTS/USRA. Call
479-394-1075 or visit www.brodix.com for more information.
relocating, grinding, polishing or defacing of any cast letters
and/or numbers is strictly forbidden.
guides must retain original angle and spacing as manufactured. Valve
guides may not be tapered, thinned or shortened whatsoever. Minimum
valve stem diameter must be five-sixteenths (.310) inch.
Absolutely no welding or adding material of any kind.
Absolutely no enlarging, relocating or other altering of any bolt
hole, dowel hole or threaded hole, except to spot face bolt holes
after angle milling.
coils are permitted for repairs.
Absolutely no grinding or polishing of any kind anywhere on the
casting, except for pushrod clearance. Factory CNC chamber may not
be altered in any way.
Internally-repaired BRODIX aluminum spec head must be recertified by
aluminum spec head checking fixtures may be used by tech officials
to check specifications and dimensions.
Option #1: USMTS/USRA Spec Engine (2,450 lbs., 5” spoiler):
cam or flat tappet cam is permitted.
16.3.2 All other
BRODIX Spec Head Rules apply (see Rule 16.2).
tappet 23-degree steel-headed engine and GM CT525 crate engine (see
17.5 for complete details) will also fall under this option.
Option #2: USMTS/USRA Concept Engine (2,400 lbs., 6” spoiler):
16.4.1 Any cast
iron block is permitted. Unnecessary machine work inside or outside
of block is not allowed. Lightening, coating, painting or any other
work to inside of intake manifolds, heads and/or block lifter galley
is not allowed.
14:1 compression is permitted.
16.4.3 Steel oil
pan only is permitted. Wet sump system only is permitted. Cast iron
oil pump must be in stock location. Oil pan must have inspection
aluminum intake is permitted. Must be seven and one-quarter (7.25)
inches from bottom of intake to base of carburetor, including spacer
mount rocker arms only are permitted. Maximum 1.6 ratio. Stud girdle
is permitted. Shaft rockers are not allowed.
valves and valve spring retainers/locks only. Hollow stem and/or
titanium valves are not allowed.
16.4.7 Cast iron
flat tappet cam with stock diameter journal, stock firing order, in
stock location, with stock diameter. Cast iron lifters only.
Mushroom lifters are not allowed.
chain only is permitted. Gear or belt drive is not allowed.
diameter “Babbitt” cam bearing only is permitted.
maximum RPM chip is required.
crankshaft only is permitted. Gun-drilled mains are not allowed.
Undercutting of counterweights is not allowed.
balancer only is permitted.
headers are not allowed.
valve covers are permitted.
other BRODIX Spec Head Rules apply (see Rule 16.2).
16.4.16 Use of a
sealed GM 604 crate engine will also fall under this option.
Option #3: Open Engine (2,500 or 2,550 lbs., 3” spoiler):
all other engines not specified in Engine Option #1 or Engine Option
ARTICLE 17: WEIGHT
17.1 The overall
weight of the racecar shall be measured after an event with the
driver in the cockpit, wearing complete racing apparel. A “burn off”
allowance may be offered at specific events where the number of laps
will exceed normal conditions. This allowance, if any, shall be
determined by USRA officials before the event begins.
racecars must display weight at which it will compete on left side
windshield post. Must be two (2) inches tall and in contrasting
color to the racecar. Any racecar not displaying their weight will
be required to weigh the maximum weight for this class and required
to add any weight in any location required in this class.
Weight: 17.3.1 If utilizing Engine Option #1 (USMTS/USRA spec
engine, 23-degree steel-headed flat tappet or GM CT525 crate engine
(see 17.5 for details), the overall weight of the racecar must be a
minimum of two thousand four-hundred fifty (2,450) pounds.
utilizing Engine Option #2 (USMTS/USRA Concept Engine), the overall
weight of the racecar must be a minimum of two-thousand four-hundred
utilizing Engine Option #3 (Open Engine), the overall weight of the
racecar must be a minimum of (a) two-thousand five-hundred (2,500)
pounds if using 23-degree steel or aluminum heads and roller cam, or
(b) two-thousand five-hundred fifty (2,550) pounds with less than
utilizing aluminum heads other than the BRODIX Aluminum Spec Heads,
racecar must have a minimum fifty (50) pounds of weight in front of
utilizing the CT525 crate engine, must use one of the two following
track options: 1. Track Option 1 – Minimum of fifty (50) total
pounds (twenty-five (25) pounds on each side of the engine) at or
ahead of front motor mounts, at or above the spark plugs height. 2.
Track Option 2 – Front axle weight of at least one thousand fifty
(1,050) pounds combined total of the front two wheels. If racetrack
utilizes one single-pad scale, racecar shall be pulled onto scale to
a point where rear motor plate (mid-mount) is just over the scales.
If racetrack uses individual wheel scales, front two wheel weights
will be added together to get front axle weight while car is on all
utilizing lightened blocks (removal of material from inside and/or
outside), an additional twentyfive (25) pounds of weight must be
added in front of the mid-plate (see Rule 16.1).
17.7.1 May not be mounted in cockpit, or outside of body or hood
17.7.2 Must be
securely mounted, painted white and clearly marked with the car
17.7.3 Must be
attached with at least two (2) one-half (0.5) inch bolts.
17.7.4 May not
be attached to rear bumper.
ARTICLE 18: SAFETY
18.1 It is
recommended that each racecar have built-in fire extinguishing
equipment, but cannot be of the dry powder type (must be Halon 1211
should have in their pit area as part of their equipment, at all
times, a fully charged dry chemical, Halon (or its equivalent) fire
extinguisher. Ten- or thirteen-pound fire extinguishers are
18.3 Driver must
wear required helmet, fire suit and five-point safety harness
whenever the racecar is on the racetrack. This includes during track
packing, warm ups, hot laps and races.
18.4 Helmets are
mandatory and must be certified SA2005, SA2010 or SA2015.
18.5 Helmet must
accompany driver and racecar at time of inspection.
one- or two-piece fire suits of a flame retardant nature are
Fire-resistant gloves and shoes are mandatory. Fire-resistant socks
18.8 The use of
a five- six- or seven-point driver restraint system (safety belts,
sub-belt and shoulder harness) is required. Factory-type shoulder
belts or straps are not allowed. The use of a seven-point driver
restraint system is recommended. Shoulder harness must be mounted to
main cage and not the tail section of car.
18.9 Metal to
metal buckles are required on shoulder and seat belts.
harness must be mounted securely to the roll cage.
18.11 Where the
belt passes through the seat edges, a grommet must be installed,
rolled and/or padded to prevent cutting of the belt.
restraint system must be less than three (3) years of age past the
date of manufacture. It is recommended that the driver restraint
system be no more than two (2) years past the date of manufacture.
window net mounted in the left side driver’s window opening is
required. Window net mounts must be welded or securely bolted to the
roll cage. All bars around the driver must have approved roll bar
padding. Approved racing arm restraints are recommended. Window net
mounts are highly recommended to be securely welded or bolted to the
inside of the main roll cage on top.
Fire-resistant safety neck collars are mandatory.
no plastic except from edge of firewall to body skin and inner wheel
tub to body skin.