2020 Midwest Modz Rules

Posted June 5, 2021

2020 updates:
New style chip box required (CT8727).
No weight added to rear axle. No heavy weight axle tubes (max .250 wall).
Quickchange option
GM 602 Crate motor option
2500 lbs minimum weight
Max & Min spring length

COMMUNICATIONS:
All competitors must have a RACEceiver 1600 in car radio to compete at the track.

FRAMES:
Factory production complete full American passenger frames only. Frame rails must extend to a point beyond the base of driver’s seat. Rear clip may be fabricated out of tubing. Front and rear pick-up loop required; otherwise bumpers or other pick-up point will be used.

BODIES:
See IMCA Northern SportMods for rear sail panel rules. Exceptions: no spoilers, no spoiler sides, no nose wings. Rule Clarification - Bodies: MD3 nose not allowed, no nose wings, window opening must be a min. of at least 12 inches on all 4 corners. Body may extend 2” on left side & 1 inch past the tire on right side. Max. deck height 39 inches. No Tolerance. Rear sail panels must meet IMCA Northern SportMod rules. No reverse hood rake.

WHEEL BASE:
108 inches minimum, 112 inches maximum both sides.

ROLL CAGE:
Must consist of continuous hoops not less than one and one-half inches outside diameter and must have a wall thickness of at least .095 inch. Must be frame mounted in at least six (6) places. Body mounted roll cages not acceptable. Must consist of configuration of front and rear hoops connected by tubing on sides or side hoops in a manner deemed acceptable by the inspector . Driver’s head must not protrude above cage with helmet on while strapped in driver’s seat. Roll cage must have a 3/16-inch inspection hole in non-critical area. Must have at least three (3) horizontal bars at driver’s door welded to front and rear of roll cage members.

WEIGHT:
Minimum weight is 2,500 pounds with driver after race, no tolerance. All lead weight must be mounted securely with 2 weight clamps and 1/2-inch bolts. Lead must be painted white and have your car number on the lead.

WHEELS:
Wheel width must not exceed eight (8) inches. No aluminum wheels. Bead locks allowed on right rear only. Any foam or plastic type mud cover mounted on right side wheels. Inner mud plug on LR only.

TIRES:
American Racer G60 only. Tires may be grooved and siped.

DIFFERENTIAL/REAR END:
Any passenger car type or truck rear end may be used.
Floater rear ends are allowed.
Any steel approved OEM passenger car or truck non-cambered rear end allowed. All components must be steel drive flange..Inspection hole in housing required.Solid steel axles and one piece drive flanges only.May have Aluminum axel caps.
Quick change option is allowed and must use 10” ring gear with aluminum or steel spool, steel axle tubes, minimum one inch wide spur gears and bolt on rear cover. Safety hubs (floater) allowed. Steel axles only. All additional components must be steel,axle caps, U-joint caps, and one piece drive flange. One inch inspection hole required in housings. No scalloped ring gears, cambered rear ends, heavyweight axle tubes (max .250” wall) or housing braces.Must have solid axels. NO gun drilled. Pinion plate must be steel.
Quick change option must run the same gear they hot lapped with.Your rear cover will be sealed by the race track . If your seal is broken automatic disqualification for the event.ONLY way you can change your gear per night is if you break a gear & you bring it to the tech official for him to ok gear change.

BRAKES:
Disc or drum brakes may be used front and rear. No aluminum disc or brake calipers allowed. Brakes must be operational on all four (4) wheels and must lock up all four wheels during inspection.

FUEL SYSTEMS:
Gasoline only. No oxygen bearing additives. No pressurized fuel systems. Fuel cells mandatory. Fuel max. capacity of 22 gallons. Must have new style screw on lip with flapper in top. Fuel cells must be encased in an approved metal container of no less than 20-gauge steel or 1/8 inch aluminum. Fuel cells must be mounted between frame rails as far forward as possible and using four, two (2) inch by 1/8 inch metal straps, two in each direction. Bumper must be equipped with a drag loop extending below bottom of the cell. No electric fuel pumps

BUMPERS:
Bumpers must be used front and rear. Front bumper must be mounted on frame end and be of a semicircle configuration with the bottom loop parallel to the ground. Front bumper must be ten (10) inches high from bottom bar to top of top bar. Material must be one and one-quarter inch minimum, two-inch maximum O.D. steel pipe. Rear bumpers may be constructed of pipe, square tubing, but must not have sharp edges. Rear bumpers and nerf bars must not extend beyond width of rear tire. Bumpers must be able to support car when lifted by wrecker.

SEAT AND SEAT BELTS:
Racing seat mandatory. All cars must be equipped with an approved quick release type seat belt and shoulder harness securely fastened to frame and roll cage. Seat belt material should be at least three (3) inches wide AND CANNOT BE OLDER THAN 2 YEARS. Seat and steering wheel may be located to suit driver’s taste, but must be kept on left side of car. No center steer.

ENGINE:
Location: Rear of engine (bellhousing flange) must be at least 72 inches forward from the centerline of the rear axle. The center of the crankshaft must be within two and one-half (2 1/2) inches of centerline of the ball joints.
Engine:.
Option A :
Maximum size of engine block: 350 gm .060 max. 351 windsor Ford .060 max. 360 Chrysler .060 max Harmonic balancer on GM min. 8 in. Smaller engine allowed no stroker engines allowed! OEM firing orders cannot be changed. No beehive or high performance valve springs allowed. 9 to 1 compression max.
Heads: 76 cc min., stock, no performance heads (no double humps, no 292,041 castings, no lt1., no bowtie, no center bolt valve cover or aftermarket allowed). No porting or polishing, no screw in studs with shoulder, no guide plates, 194/160 valves max. no 202/160 allowed. 305 heads on 305 only!
Camshaft: Hydraulic camshafts only &must pull at least 15 inches of vacuum at 1000 RPM. no tolerance. Hydraulic cam 430 maximum lift at valve, stock 1.5 ratio rockers only, no tolerance. Poly Locks permitted. No roller cams. No roller tip or roller rockers allowed. Lifters stock type, no Rhoades, anti pump up, high revolution, etc . Stock type wire clip.
Crankshaft and Rods: Stock appearing, no light weight, no H-beam rods. Press fit rods only. No floating rods, 5.7 rod on GM max. Aftermarket Eagle, Scat, etc. stock type ok. No lightening of any kind to crankshaft, 3.48 stroke max.
Pistons: Flat top 4-valve relief only. Hypereutectic 4-valve relief pistons ok. No JE, Ross, etc. No high performance parts allowed.
Balancer: No modifying of harmonic balancer, 8.9 lbs. min.
Intake manifold: Only intakes allowed are GM 2101, ford 2121 or 2181, chrysler 2176 or 3776. Intake must be unaltered (part #2701).

Option B:
CRATE ENGINE: Must use unaltered sealed GM 602 crate engine with additional IMCA Cable-Lok system or USRA seals NO EXCEPTIONS. Upon inspection, any different, altered or missing GM seal bolts or IMCA Cable-Loks,USRA seals will result in a penalty of 1 week suspension and a $500 fine. Legal aftermarket oil pans ...Champ pan #CP100LTRB and Champ pick-up #100SB, or with Kevko pan IMCA92 and Kevko pick-up #1005-3/4.
-602 GM crate engine MUST run a 6,000 rpm chip.
-Carburetor rule will be the same as motor option A.
-Engine must pull a minimum of 15” of vacuum at 1000 rpm.
TRACK HAS OPTION TO ENFORCE THESE RESTRICTIONS WITH A CUBIC INCH PUMP GAUGE OR BY VISIBLY CHECKING PARTS AND PART NUMBERS. DISQUALIFICATION AND LOSS OF POINTS IF FOUND ILLEGAL.

SHOCKS:
One steel, nonadjustable, unaltered shock per wheel only. No take apart shocks. No external gas ports of any kind. No screws. No Schrader valves. No ports, none. All shock mounts, including screw jack type, must be welded. Must have 1” minimum of shock travel up & down at ride height with driver in car .No external or internal bumpers or stops. No coil over, air or remote reservoir shocks. No Schrader valves or bladder type valve allowed. Front half of any shock may be shielded. One or all shocks may be claimed per event for $75 each.

FRONT SUSPENSION:
FRONT SUSPENSION MUST MATCH FRAME AND BE IN STOCK LOCATION. PARTS MUST BE REPLACEABLE FROM STOCK OEM TYPE PARTS FROM SAME TYPE SUSPENSION EXCEPT UPPER A-FRAME AND A-FRAME MOUNT. TUBE TYPE UPPER A-FRAME MAY BE USED. FABRICATED A-FRAME MOUNT MAY BE USED BUT MUST BE IN STOCK LOCATION. LOWER AFTERMARKET A-FRAME CAN BE USED BUT MUST BE IN STOCK LOCATION. NO FABRICATED SPINDLES. ADJUSTABLE STRUT BARS CAN BE USED ON FRONT END ONLY. NO COIL OVER SHOCKS ALLOWED EITHER FRONT OR REAR. ONE SHOCK PER WHEEL.YOU MAY NOT RUN A DAMPENING SHOCK ABOVE THE REAREND. STEERING BOX MUST BE STOCK OEM TYPE AND BE IN STOCK LOCATION. NO RACK AND PINION STEERING. NO CENTER STEERING. ADJUSTABLE SWAY BARS ALLOWED.FRONT SPRINGS MUST BE STOCK METRIC DIMENSIONS & CHEVELLE MUST BE STOCK DIMENSIONS.

REAR SUSPENSION:
TWO OPTIONS: AFTERMARKET THREE LINK DESIGN OR MULTI-LEAF SPRING DESIGN. ALL COMPONENTS MUST BE STEEL. ALL MOUNTS AND BRACKETS MUST BE WELDED OR BOLTED SOLID. YOU MAY NOT RUN A DAMPENING SHOCK ABOVE THE REAREND.
THREE LINK DESIGN REQUIREMENTS - MUST USE MINIMUM 16 INCH CENTER TO CENTER OF HEIMS LOWER TRAILING ARMS BOTH SIDES NEEDS TO BE THE SAME, (1/2 INCH TOLERANCE), NO SWING ARMS. SOLID PULLBARS ARE REQUIRED, NO SPRING BARS, RUBBER BUSHINGS OR ANY TYPE OF TORQUE DEVICE. PULLBAR MUST BE MOUNTED SOLID (NO RUBBER OR ANY TYPE OF CUSHION IN THE MOUNTING BRACKET). MUST BE LOCATED AT TOP CENTER OF REAR END HOUSING AND REMAIN CENTERED ON HOUSING OVER DRIVE SHAFT (1 INCH TOLERENCE LEFT TO RIGHT). MAY USE MINIMUM 23 INCH LONG PANHARD BAR LOCATED BEHIND REAR END HOUSING OR MINIMUM 19 INCH LONG J-BAR MOUNTED TO A STEEL PINION BRACKET. MEASUREMENTS ARE FROM CENTER OF HEIM JOINT TO CENTER OF HEIM JOINT. MAY MOUNT REAR SPRING OVER AXLE HOUSING OR USE COIL COVER ELIMINATORS (SLIDERS). LOWER SPRING PERCH OR COIL COVER MOUNT MUST BE WELDED TO REAR END HOUSING. NO BIRDCAGES OR FLOATING MOUNTS ALLOWED. MUST USE STEEL UPPER WEIGHT JACK IF SPRINGS ARE MOUNTED OVER AXLE HOUSING. NO SHOCK TYPE ELIMINATORS.
MAXIMUM LENGTH REAR SPRING 16”.
MINIMUM LENGTH REAR SPRING 11”.

CARBURETOR:
4412 Holley, no modifactions except jets and choke removed (not choke tower). Carburetor is subject to claim by any driver in a feature in lead lap. Claim is $250 outright or $175 with exchange. Failure to sell forfeits points and finish for the night plus 2 weeks suspension and $50 fine. No electric fuel pumps, manual only. Spacer plate for carburetor from intake to carburetor only, claim $25 outright or $15 with exchange. Carburetor must have vacuum ports for testing vacuum. Carburetor spacers 1 inch max. No tapered spacers.

OIL PANS:
Extra capacity oil pans are permitted. No dry sumps allowed. Oil pump must mount in stock position. Must have 1 inch inspectoin hole above oil level for inspection. Inspection hole needs to be installed in a manner so that official can see crankshaft and rods for proper inspection otherwise pan will be removed for inspection.

STARTER:
Engine must have working starter and must be capable of starting car on demand.

TRANSMISSION:
OEM three-, four- and five-speed and automatic production-types are permitted. 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. In-and-out boxes are not allowed. Ball spline transmissions are not allowed. May all be clutch-operated or an OEM automatic with a coupler. May use a hand or clutch pedal operated ball valve for neutral.
Aftermarket transmissions are permitted.
Approved aftermarket transmissions are Bert (part #BERLMZ), Bert 2nd Generation are not allowed; Brinn (part #70001), Falcon (part #60100), RaceGator (part #140002/140002-C) and Mitchell Machine Bullet Tranny with internal clutch. Clutch must be inside of bell housing for OEM production-type transmissions.
Starter must bolt to engine block or factory location.
One (1) forward gear and one (1) reverse gear must be in working order, plus a neutral position, and must be able to be shifted by driver.
Aluminum flywheels are not permitted. Must have full-sized steel bell housing. Flywheel must bolt to crankshaft. Clutch must bolt to flywheel, a minimum six and one-quarter (6.25) inch clutch.
Automatic and aftermarket transmissions must have a guard 270 degrees around flex plate or flywheel, and must be constructed of at least one-quarter (0.25) inch steel. Alternatively, automatic transmissions may utilize an SFI-certified aftermarket guard. Flex plates must be SFI certified.
Internal clutches are not allowed except for approved aftermarket transmissions.

DRIVESHAFT:
Minimum two-inch diameter, white, steel driveshaft. 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.

BATTERY:
All batteries must be mounted in a safe manner. Top of battery must be covered.

HELMETS & FIRESUITS:
Helmets are required and must be worn at all times car is on the track.Snell-rated SA2010 or SA2015 helmet required. Roll bar padding required in driver compartment. Recommended: Fire retardant padding. ALL Drivers must wear a SFI-approved full fire suit. Two-piece suits are allowed. Fire-resistant gloves are mandatory. Fire-resistant boots are highly recommended..

EXHAUST:
Any collector type header allowed. Exhaust must be directed away from areas of possible fuel spillage. No Zoomies. No 180 degree headers. No step down or Y-type headers.

KILL SWITCH, FIRE EXTINGUISHER & WINDOW NET:
A kill switch is required within easy reach of the driver. This switch must be clearly marked OFF and ON.
Weights and/or loose objects are not allowed in the driver’s compartment.
All cars must be equipped with quick release type window net on driver’s door.
No rear view mirrors of any kind.
No radio communication or sound equipment of any kind.

GAUGES/ELECTRONICS:
Mandatory MSD (part #8727CT) rev control box is permitted with unaltered wiring harness
(motor option A max RPM setting must be 6,200 / motor option B max RPM setting must be 6,000). 12-volt ignition system only. HEI distributor only. OEM firing order cannot be changed. Ignition rotor, cap, coil and module must remain OEM appearing. No ignition boxes, remote coil or accessories. All wiring must be visible for inspection. Only gauges allowed are analog oil pressure and water temperature and analog tachometer (memory recall allowed). No electronic traction control allowed.

These rules are written and interpreted by the race track and tech officials, not the drivers. If doesn't say you can't, it doesn't mean you can.