Modified Four

2018 Modified 4

These rules are for our weekly races. If an MMSA event is scheduled, we will comply with ALL MMSA rules for that night.

Changes will be underlined

All cars must have a roll cage that has been approved by the track. All drivers MUST wear a full fire suit (jacket and pants). Gloves, racing shoes and window nets are recommended. All cars MUST have a working Fire extinguisher within the reach of the driver. Driver is not to exit car unless it is on fire or upside down. If driver exit’s car for any other reason is subject to be disqualified. NO TWO WAY RADIO’S, Raceceiver only, mirror’s OK. It is also recommended to have a full containment seat or head / neck restraint device. You will be given a 25lb weight break TOTAL (this is for 1 NOT each). All added weight MUST be secured by ½” bolt and painted white with car # on it.


Racing fuel or pump gas only.


A) Any two or four door foreign or domestic car with a 94-101.5 wheelbase. Wheelbase must match make and model of car.    B) May have a complete aluminum body but must retain stock shape and appearance.(See Body Measurements) C) Inner panels may be removed. D) NO FWD or MID Engine Cars E) Must have floor pan on both sides to rear of front seats. F) Must have a rear firewall or drivers compartment must be boxed in G) After market nose piece OK. MD3 nose OK molded fenders MUST MOUNT FLUSH on top and sides of fenders and no wider than 1 inch outside of tires. (NO WINGS / ELEPHANT EARS) H) May run a 6 inch rear spoiler – can’t go over side of quarter panel – no wider than the width of the car – spill plates OK spill plate measurements bottom is 16 inches rear 8 inches high 4 inches across the top rear and 4 inches high in the front.
I) Interior spoiler no more than 4 inches high and NO higher than dash. J) Rear bumpers must NOT extend past the inside of the rear tires unless it has a bumper cover or turns forward (if turned forward must be on a 90° angle NO SHARP CORNERS / EDGES) K) Nose 70-inch maximum width. L) 68-inch maximum width at ANY point. M) 38-inch maximum ground to deck (bottom of spoiler). N)  Aluminum ok to close rear of car MUST come down to frame rails. 14” Minimum from deck to frame rail. (No holes or flaps) O) May use lexan in rear windows. P) Must run hood.  Q) Breather may stick through hood. R) Cold air box ok but air holes in hood only not in firewall. S) May have heat shield under hood. T) May have hole in firewall big enough for the header to pass through (tech discretion if hole is to big). U) May replace top ¼ of firewall with steel or aluminum (this doesn’t mean the whole firewall) no lower than original master cylinder hole in firewall. No holes above or below the deck.

** Acceptable body infractions will result up to a 50lb weight penalty in the area of the infraction**

** All body infractions are not acceptable tech mans discretion**

Chassis / Suspension:

A) Must have a roll cage and all safety equipment. B) Roll cage must be secured to the unibody. C) Tube Chassis Allowed. Must weigh 2500lbs. D) May tie chassis together by splitting floor pan and put square tubing in from the top and may stick through floor pan BUT NOT totally underneath. NO “X” Bracing Under Floor Pan. E) Square / roll cage tubing from strut towers forward is acceptable. F) May use square tubing or roll cage material from back of shock mounts to rear of car must be straight no angling of material. G) All A frame, trailing arm’s and springs must be stock and mounted in STOCK location (may cut lower A frame for caster / camber adjustments)
H) May cut Top trailing arm (s) or re drill for pinion angle only. I) Lowering blocks ok J) Caster / Camber plates ok K) Adjustable buckets or Jacking Bolts are ok, but MUST remain in STOCK location (Buckets or Jack Bolts may be raised for spring travel). If not in STOCK location you may be subject to a weight penalty. Buckets or Jack Bolt Must Be In Fixed Location. (Tech’s Discretion) L) Ford may run coil over on front struts. M) May cut upper or lower control arm for caster / camber. N) May cut pan hard bar must be NON ADJUSTABLE. Must be located in STOCK location. O) Mono Balls Allowed P) Stock Mounted body shocks may have heims (bottom only) shocks may be adjustable (dampening) NO CANISTER STYLE SHOCKS ALLOWED Q) May adjust shocks for travel but not change the angle of the shock (not mounted to roll cage)(No adjustable bracket)  R) Offset in steering rack ok S) Bump steer Not Allowed (NO heims or shims/ spacers) T) ** If any suspension component not in STOCK location you will be subject to a weight penalty. U) ** $150 buy rule per shock ** This is for shock only! V) ** $300 buy rule per strut ** This is for strut only NO SPRING!

Brake System:

A) 4 wheel disk brakes permitted must have OEM components B) Dual master cylinder permitted. C) 3 wheel brake shut off permitted  D) No adjuster for brakes from front to rear in reach of driver. E) Stock rotors and drums No lightening but may remove caliper and rotor on RF Only (Ford on a Ford Toyota on a Toyota).

Wheels & Tires:

A) Wheels Steel 8” maximum width.  Bead locks ok (bead lock must face outward).
B) May have bead locks on all 4 wheels. C) Hoosier 400’s only (NO GROOVING or SIPPING) D) No prepping at track; NO CREOSOTE E) Needling allowed

Rear ends:

A) Any stock up to 8.8 for make of car. B) No gun drilled axles (may weigh axles to compare if necessary) C) No full spools D) Mini spool OK E) Housing cannot be modified for gear clearance. F) May lock rear end by weld, mini spool, limited slip (limited slip unit must be stock NO aftermarket units). G) NO RATCHET SPOOL ALLOWED! H) If spider gears are removed you must claim lightened gear and add 25lbs. I) Cut gears must add 25lbs. J) If gears are polished must add 20lbs. (if cut and polished add both penalties)

** ENGINE: ALL Engine Core Parts (ex: Block, Head, Crankshaft and Intake) Must Have Been Available on Cars or Trucks Sold to the General Public by Mass Production. All Parts Must Be OEM of the Same Brand Vehicle You Are Racing. NO FRONT WHEEL DRIVE, MARINE, INDUSTRIAL OR SPECIAL PRODUCTION PARTS PERMITTED.**
Engine option #1 S.C. Stock 4 type weight: 2300lb Minimum. See CC’s weight:

A) Stock engine location – no set backs. B) No engines with more than 2 valves per cylinder. C) Ford in a Ford: Toyota in a Toyota. D) No rotary or turbo or double over head cam engines permitted E) OEM blocks only .080 over bore max. 5cc for wear – not to exceed 2500cc + .08 over bore. F) Ford may Sleeve a 2300cc block to a 2000cc. G) Aluminum cam gear or pulley allowed. H) Any Steel connecting rod- no aluminum or titanium. I) NO titanium wrist pins. J) Only Babbitt style bearings Allowed (No roller bearings) coated ok. K) Stock crank with stock stroke ± .01 tolerances. L) NO AFTERMARKET CRANKS. (stock lightened crank must add 50lbs in front of firewall) M) All engines must use an in-block wet sump oil system. N)  Racing oil pans permitted. O)  NO dry sumps allowed. P) Any flat top piston – Toyota 1600 and 1800 may run dome of .235 tall only. (.267 dome must add 50lbs) Q) Formula for cc’s- bore X bore X .7854 X stroke X 4 = cid then divide cid into .061= cc’s.  Tolerance is 5cc for wear. R) May have E-Vac to header only NO VACCUM PUMPS. S) May run electric water pump. T) May run electric fuel pump. U) Ignition – stock or Mel’s Ignition ONLY (NO BOOSTERS on Ignition). (No Traction control allowed)(NO ECU Units) (NO MSD Style)(NO MSD Style Ignition Boxes) V) Single Ignition coil Only.  W) Radiator must be mounted in front of engine.


A) MUST HAVE BEEN AVAILABLE ON PRODUCTION CARS/ TRUCKS FROM OEM AUTOMOTIVE FACTORY B) OEM may be changed from one size engine to another without modification. C) May have competition valve job with any angle or depth must not touch bottom of valve boss. D) All angles MUST be concentric with valve guide.
E) Any steel valve stock diameter may be undercut stem + .009 tolerances. F) Valve stem must be stock diameter for year model of head. (No 7mm valve stem in a Ford) G) Double valve springs ok must be steel H) Beehive valve springs ok must be steel I) Any steel retainer J) Lifter has to be stock diameter – solid ok K) NO PORTING or POLISHING


A) MUST HAVE BEEN AVAILABLE ON PRODUCTION CARS/ TRUCKS FROM OEM AUTOMOTIVE FACTORY. B) OEM may change from one size engine to another without modification unless stated. C) No fuel injection manifolds D) Must be single carburetor. E) No side draft intakes. F) OEM style gasket only. (.07 max thickness) G) May modify for carburetor but must be approved before race by MMSA tech. H) May bore straight down for clearance  – NO TAPERING, RADIUS or BLENDING. I) Intake gasket is part of intake protest.


A) Stock carburetor or Holley 350 cfm (#7448 or 0-80787-1) or Holley 500 cfm #4412 must pass no go gauges. B) Must have air horn with number. C) Float bowl must face forward D) May cut end of screws and have holes in butterflies E) No thinning of shafts F) No polishing or grinding G) Spacer and adapter – any 1” max thickness together – NO TOLERANCE. Spacer cannot protrude into intake. H) 2 gaskets @ .07 thickness maximum each


A) Any header. No Tri-Y.


A) Solid or Hydraulic NO ROLLERS B) Maximum .425 lift at valve with .025 lash at valve for solid C) Hydraulic ANY LIFT D) Hydraulic lifter must collapse or be taken apart for inspection E) No swapping of any lobes – must be in stock order F) No roller or needle bearings stock type only coated ok

Flywheel & Clutch Assembly:

A) Stock flywheel must weigh 16lbs B) Must have stock or stock replacement clutch and pressure plate C) NO LIGHTENING OF PRESSURE PLATE D) Only grinding, adding weight or drilled holes to pressure plate for balancing. Drilled hole size is 7/16 diameter max (NOT all the way around pressure plate). If there are holes all the way around pressure plate it WILL be considered lightening. E) Studs for pressure plate ok (must be a purchased stud, no custom machined studs allowed) F) Cannot relocate pressure plate bolt hole pattern G) Scallop flywheel add 50lbs


A) MUST BE STOCK with all working forward and reverse gears. B) Cannot remove or lighten drive or reverse gears. C) May remove speedometer gears only.


A) Minimum of 1 ½” diameter B) Must be steel C) Must have a safety loop D) Must be painted white with number on it.

Engine Option #2 Ga Rules Cars 2300 Fords Only 2300lbs.:

Bottom End:

A) Stock crankshaft NO lightening B) .060 over bore permitted C) 5.2 rod only can be aftermarket steel D) May use racing oil pan E) No dry sump F) May be balanced G) May run E-Vac NO VACCUM PUMPS H) Ignition – Stock or MEL’s Ignition only I) Radiator must be mounted in front of engine


A) Must be stock for make and model and available on cars from factory B) Stock 1 piece replacement valve permitted (can be single lock groove). Racing valve springs permitted. C) Any hydraulic (.455 lift max.) cam permitted. Checked with a solid lifter @ 0 lash. D) Cam gear permitted E) Stock cast iron manifold or header permitted F) Shims under lifter permitted G) NO PORTING & POLISHING PERMITTED

Intake Manifold:

A) Stock intake and stock fuel injected (with adapter) permitted. **Note EFI intake used only with GA rules** B) No sidewinder intakes permitted C) No porting or polishing


A) 1” spacer or adapter permitted
B) Holley 350 (7448) or 500 (#4412) carb. permitted. No polishing and porting. Must pass no go gauge. C) Carburetor float bowl must face forward D) Holes in butterflies ok

D) .455 hydraulic head GA stock 4 type rules may run tri-y.

CC Weight’s, Weight Break’s and Penalties:
A) Toyota 2tc & 3tc must weigh 2300 lbs. minimum  B) Ford 2.0 must weigh 2300 lbs. minimum C) Any other than listed must weigh 1lb per cc (2300lb minimum) D) HANS / Full Containment Seat –25lbs (1 or the other not for both). This weight break is in effect at all times. E) Scallop Flywheel +50lbs F) .267 Dome Toyota Only +50lbs G) Cut / Lightened Ring Gear +25lbs H) Polished Ring Gear +20lbs I) Lightened Crankshaft +50lbs (in front of fire wall) J) 5lb tolerance at scales. K) CC’s and all weight breaks / penalties, and weight TOTAL MUST be listed on each side of front fenders or hood. All breaks and penalties should be told to tech at pre-race inspection for documentation. If not listed or documented track has the right to DQ after qualifying or main feature. L) Any exhaust exiting from body panels must no be more than 1/2″ past panel.

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