2024 Zimmie’s Auto Service A – MOD RULES (Updated 8/16/23)
Points Awards – 1st place – $1000- Must run sponsor sticker on car and attend Awards Banquet to receive post season awards.
No Gas Charged Shocks
Any differences in these rules please call and we will try to accommodate!!!!
NO CARBON FIBER. NO TITANIUM UNLESS OTHERWISE NOTED. NO BUMP STOPS. NO BUMP SPRINGS
OR CHASSIS LIMITERS. NO TRACTION CONTROL DEVICE(S) OF ANY KIND.
**Speedway officials shall be empowered to permit minor deviations from any specifications here in or impose any
further restrictions that is his/her opinion does not alter the minimum acceptable requirements. No expressed or
implied warranty of safety show result from such an altercation of specifications.
Speedway reserves the right to update, modify and/or delete rules at anytime deem necessary to ensure safety, fair
competition or any other reason that may be appropriate.
CAR:
American made, factory production, 1970 or newer with parallel frame, rear wheel drive only. Minimum wheel base
108”. Wheel base must be within 1/2” side to side.
Chassis:
A. OEM stock for chassis clips or fabricated / tubular frames (must be approved by tech.)
B. Frames may not be widened or narrowed and must be able to support roll cage on both sides. Front cross
member may be notched for radiator clearance only. No widening or fabricating of cross member. Must maintain
stock measurement from cross member to A frame bolts.
C. Stock clip cars 58% left side max. Fabricated clip cars 58% left side max with 50 pounds in front of flywheel.
D. Ride height minimum of 4” to body, frame and lead at all times. No pulling up on car in tech line.
E. MODIFIED TUBE CLIP. Must use stock lower A-Frames, steering box and idler arm. Must maintain 3-¼” from
lower control arm bolts to bottom of cross member at all times. Lower mounts must be solid and non-adjustable. Must
measure 17” – 1/4” tolerance from center bolt to center bolt on front side of lower control arm and 27” – ¼” tolerance.
Any tube clip that doesn’t meet the specs will be deemed illegal.
F. Adjustable Idler arm allowed but MUST be mounted in stock location.
BODY:
A. Width 66 inches maximum length 120 inches maximum measured from front of door / back of engine block to the
end of rear quarter at any point. 6” maximum body rake. Maximum 3” at door and 3” at quarter to get the 6” total.
Body must be mounted straight on chassis.
B. Firewalls can be aluminum and floorboards are to be made of steel only.
C. Fiberglass, aluminum or steel duplicates of body parts are permitted.
D. Full roof is mandatory and must cover complete halo bar. Maximum of 21 inch drip rails allowed.
E. Original roof line of vehicle should be maintained with a maximum of 1” drop rear to front.
F. No wings, ledges or other ground affects anywhere inside or outside car.
G. Rear spoiler allowed 6“ x 60“ only.
H. Engine compartment will remain open, no side panels. Hood sides may have a maximum of 6” drop and be
enclosed at the rear of the hood. Bodies should extend no further than back of the block. NOTE: (passenger side of
body must be no further forward then the rear of the block).
I. Lower rear quarter panel turn not to exceed 1 inch maximum with a maximum of 2-1”braces/supports. Quarter
panel minimum height from top to bottom in rear is 18”.
J. Windshield must cover at least driver side 1/8” lexan only. Rear window optional. If used must be lexan. 1/8” lexan
only.
K. Maximum front nose width 43 1/2”
L. Side window curtains must stop 6″ from spoiler
ENGINE:
A. 350 block only two bolt or four bolt main block. 350 crank only. Builder option. No studded blocks. 060 maximum
overbore +.010, zero deck builders option. No grinding in block, screens OK. No overbore of lifter holes or repairs.
B. Heads stock open chamber head with stock valves and 100 lb seat pressure or EQ heads with IMCA hobby heads
76 cc 1.94 intake and 1.50 exhaust. Three angle valve job allowed. No bowl cutting, flat cut only 72 CC chambers,
Diameter equals 1.250 maximum diameter. Stock rocker nuts and balls. World Products 4360KA heads Legal as well
C. Any flat top 2 or 4 eyebrow piston. Pistons may not stick out past top of block. Must be stock length full skirt piston
D. Rods 5.7 rod length ( stock OEM ) only for engine used. No aftermarket. No stroking or de-stroking of engine
allowed. No H-beam rods.
E. Crank- After market cast crank 48 lbs no knife edge. Balancing OK. Stock stroke and weight for engine used.
F. Camshaft 390-410 lift cam with 650 Quadrajet allowed or 450 lift cam max with 500 cfm Holley 2 barrel (4412) or
Holley 650 Part # 80541-1, 80541-2 Only. Must pass track gauges. Camshafts may be degreed
Stock rocker ratio for engine used. 1.5 GM steel rockers OEM lift will be checked out at rocker. No stud girdles. Screw
in studs and poly locks OK. Stock OEM GM lifters. May run double roller chain, non-adjustable gear.
G. Intake. Stock cast Quadra- jet or may run performer 2101 series intake. No bowtie, Corvette or boat intakes
allowed. (Maximum 1” carb spacer.) NO Air box to carb or air cleaner
H. Distributor stock only GM HEI (NO MSD boxes). Only MSD soft touch rev limiter is ok to use 6300 chip rule and must be out of reach of driver
I. Push rods. stock diameter.
J. Water pump steel or aluminum. Stock style harmonic balancer or, OEM GM for engine used. Oil pan, valve cover and
pulley builders option.
K. L88 flywheel OK 14 lb minimum
L. 602 steel head GM crate motor allowed with 500 CFM Holley 4412 carb.(C or CT) Or Holley 650 4150 Part #
80541-1 or 80541-2 0nly
M. Built 350 or 602 crate motors. Per rules. ( 604 engines with 602 heads & intake NOT allowed). ( No 603 crates ) (ALL Unsealed crates must run 500 Holley 2 barrel carb– checked with tech tools)
N. 602 Crate may use aftermarket oil pan for ground clearance
O. Exhaust system must be mounted in such a way to direct spent fumes away from the cockpit of vehicle and must
extend past frame rails and away from all areas of possible fuel spillage. All headers are allowed.
P. Rear of the engine (bell housing flange) must be mounted at least 72” forward from the centerline of the rear axle.
Engine offset must be kept within the front stub. Engine offset maximum of 2” of centerline of front cross member.
Crankshaft minimum height will be 11” from the ground to the center of the crankshaft. Must be wet sump only. No
totally dry sump systems allowed. Wet systems must be operative.
Engine Blocks:
GM 350
Ford 302, 351
Chry. 318, 360
Heads:
GM 72cc min.
Chry. 64cc min.
Ford 60cc min.
Stock Diameter valve springs for heads used. 100 LB max seat pressure
TRANSMISSION:
A. Saginaw 3 speed or 4 speed, Muncie four-speed and turbo 350-400 automatic transmission allowed. 10” inch
minimum torque converters. No lock up converters. No five speed transmissions, No in/out boxes. No buttons or
couplers. Must all be clutch operated with motor running and car still in position. Driver must be able to engage car in
gear and move forward, then backward at time of inspection. Clutch must be inside bell housing. Must have all
forward gears working and reverse. No light weight parts or straight cut gears.
B. Clutch size minimum 5 1/2 inches. Must add 50 lbs for any clutch smaller than 10” inches.
C. Stock OEM transmissions allowed, Power glide transmission allowed. NO RACING TRANNY’S ALOUD
DIFFERENTIAL:
A. 9 inch floater or quick change. 10 or 12 bolt Axles must weigh 7 lb each minimum, No twist axles
B. Wide 5 hubs allowed with bolt on front adapters to stock spindle, stock lowers only. Must remain in factory
location.
C. No rear sway bar.
WHEELS & TIRES:
A. Any 60 or 70 series DOT tires with minimum tread-wear rating of 400. Must be seen on tires. Tires may be cut or
trued. No tire soaking allowed. TIRES MUST NOT BE PUNCHED LOWER THAN 54, MUST BE HIGHER DURAMETER
B. Wheels maximum with 8 inches. Steel only. Must be racing wheel. Tires must not to be outside Nerf bars.
C. 80 inch tread width maximum outside to outside. No tolerance.
D. No bleeders
ROLL CAGE:
A. Must consist of continuous hoops, not less than 1-¾” outside diameter must have a wall thickness of atleast .095.
B. Must be frame mounted in at least 6 places.
C. Must consist of configuration of front and rear hoops connected by tubing on the sides or side hoops. Drivers
heads must not protrude above cage with helmet on and strapped in driver seat. Roll cage must be securely
supported and braced.
D. Protection of feet is mandatory. Bar across back of engine with vertical bars and rub rails or similar protection.
E. No brace bars forward of cage may be higher than stock hood height.
F. Driver door bars must be as parallel with the ground as possible and located perpendicular to the driver so as to
provide maximum protection for driver without undue difficulty in getting into or out of vehicle. Sidebars must be
welded to front and rear of metal cage members. Door bars less than .095” thickness should have 4 bars at least
1-1/2” diameter. Must have steel plate covering drivers door area.
G. Must have five point harness with date specifications.
H. Window nets Mandatory
BUMPERS:
A. Must be used in both front and rear. Front bumper should be mounted frame end to frame end with bottom loop
parallel to the ground. Should be made of 1-1/4” pipe and must be welded to support car if lifted by wrecker.
B. Rear bumpers. Nerf bars. And bodies must not extend beyond width of the rear tires and must not contain any
sharp edges. MUST BE ROUNDED CORNERS
C. Rear bumpers may be constructed of pipe, flat stock or Aluminum I-beam and must protect fuel cell. Center
bumpers front and rear must be 18” (plus or minus 2” from ground.
FUEL CELL:
A. Maximum of 22 gallon fuel cell mandatory. Cutting of trunk for the fuel cell is permitted. Fuel cell must be in 22”
gauge steel.
B. Sunoco spec. fuel optional
DRIVE SHAFT:
A. Must be steel driveshaft ONLY. NO aluminum or carbon fiber
SUSPENSION:
A. Stock passenger car spindles only. No fabricated spindles. Center of ball joint to center of tie rod must be stock
measurement as well as the same measurement on both sides.
B. OEM Bottom A-frames cannot be moved. Ford lowers are allowed as long as they mount in stock mounts.
C. One piece OEM or aftermarket sway bar only.
D. No coil over shocks. Either front or rear. Coil over eliminators must be used in rear only with minimum spring
diameter of 4-1/2”.
E. No fiberglass springs allowed. No torsion bars allowed in rear.
F. No hydraulic. Ratchet or electric weight jacks anywhere in or around car.
G. One shock per wheel only. Steel non adjustable and non-rebuildable shock only. No Schrader valves. Adjustable
shafts and canisters are not permitted. No Aluminum shocks permitted. No split valving, must be same up and down.
($125 claim rule per shock). Shocks Must Be Straight up 3 to straight up 7 ONLY Meaning 3 up 3 down, 7 up 7 down
Non rebuildable shocks cannot be modified/altered shocks. Part number must be on shock
H. Heim joints on inner and outer tie rod OK. No racks.
I. Front rotors may be re-drilled for larger studs or different lug pattern but may not be lightened.
J. Front Coil Springs must be 500lb minimum. No exceptions. ( NO CUT SPRINGS ALLOWED) Spring rate weight must be on spring with part #
K. No lift bars allowed. No exceptions
COMMUNICATIONS:
A. Raceivers required.
B. Radios and spotters allowed
WEIGHT:
A. 2650 minimum with 58% left side maximum
B. Weight and left side percentage can be checked at ANY time before, during or after time trials and or racing event
with driver sitting in the normal driving position with helmet and fire suit.
C. Tube clip cars must add 50 pounds in front of flywheel. D.
Stock clip cars 2650lbs, small clutch add 50lbs = 2700 lbs total. Tube clip cars 2650lbs, with 50lbs in front of
flywheel, small clutch add 50 lbs = 2700 lbs
BRAKES:
A. Brakes must lock up all 4 wheels during post inspection. All 4 brakes must work.
B. Front and rear brakes must consist of stock appearing components single piston only.( Aluminum ok)
C. May run steel or aluminum front safety hubs. May run after-market rear hats and rotors
D. Brake Bias ok to run.
***** The rules are in addition to the general track and safety rules. It is your responsibility to know the rules, a claim
of ( I didn’t know or you didn’t specify ) will not release you from liability of the rules. Tech inspection has final say on
all issues. That call is nonreversible. If it does not say you can do it, don’t do it. If you feel a rule is not clear ask
questions, rules are not open for personal interpretation.******