SIMS Limited Modified Rules
January 1, 2004 thru December 31, 2008
© 2002-2005. SIMS. All rights reserved.
Check with SIMS for rule changes

IF IT DOESN'T SAY YOU CAN
THEN THAT MEANS YOU CAN'T!!!

• To race at any SIMS-sanctioned track, you must be a member in good standing with SIMS.

• To collect your purse at any SIMS track you will have to present a current SIMS membership card or a receipt of purchase.

These rules have been interpreted to be track and racer friendly.

At any time, any SIMS-registered driver may protest any visible or non-visible part on another car for a fee of $100 per part.

• If the car being protested is found legal then said car shall receive $50 with $25 going to the track and $25 going to SIMS per part.

• If said car is found illegal, the protester will receive $50 with $25 going to the track and $25 going to SIMS per part.

It is at the tracks' discretion on what tech procedure to use.  

We hope that the simplification and clarifications of these rules make for a great future for all.

CAR REQUIREMENTS AND SPECIFICATIONS

Mid-size GM 1978-1987 metric full frames only with 108” wheel base as per OEM specifications of stock. All frame bolt holes must remain in stock location. Wheelbase will be checked with a minimum of 107” and maximum of 109”.

WEIGHT:
2350 pounds minimum.

CARBURETOR:
You may only run one carburetor on intake.
A. Chevrolet:  Quadrajet, Chevy two barrel, Holley #4412, or #0-80583-1 two barrels.
B. Ford:  Motorcraft two or four barrel, Holley #4412, or #0-80583-1 two barrels.
C. Mopar:  Carter or AFB two or four barrel, Holley #4412, or #0-80583-1 two barrels
D. Carburetor spacer/adapter is allowed, but must not exceed 1-1/4" total thickness including gaskets.
E. Carburetor must be stock and unaltered with only one exception:  Circle track floats may be used. Holley must have choke horn attached.
F. No Edelbrocks or similar hi-performance carburetors allowed.
   
ENGINE:
A. Only 283, 302, 305, 307, 327 and 350 blocks can be used for Chevrolet. No big blocks. OEM only.
B. Only 260, 289, 302 and 351 blocks can be used for Ford. No big blocks. OEM only.
C. Only 273, 318, 340 and 360 blocks can be used for Mopar. No big blocks. OEM only. No hemis.
D. All casting numbers must remain on blocks. No side bolt main blocks allowed.
E. No Pontiac, Oldsmobile, Buick, Rambler, Studebaker, etc., motors. We realize some of these cars came with Chevrolet motors, but casting numbers will bear this out and those Chevy motors will be legal.
F. No 400 small block or big block crankshafts allowed! This goes for Ford, Chevy or Mopar.
G. No 4-cylinders allowed. No V-6’s allowed. No in-lines. V-8’s only.
H. Again:  only Ford, Chevy or Mopar engines are allowed.
I. Mopar = Chrysler, Plymouth and Dodge. 370 cubic inch maximum.
J. Ford = Ford and Mercury.  360 cubic inch maximum.
K. Chevy = Pontiac, Buick, Oldsmobile as long as they are Chevrolet engines. 368 cubic inch maximum.
L. No tolerance on cubic inch.
M. Compression may not be over 175 lbs. per cylinder on any cylinder. Track's discretion on cylinders checked. No tolerance.

CHEVROLET : FORD : MOPAR:
A. Flat top cast pistons only. No forged of any kind. Decking block okay. Chevy must be 4 valve relief.
B. OEM blocks only. No Dart or after market blocks. No aluminum. Cylinder sleeves okay. Polishing lifter galley, okay.
C. Stock OEM rods. Balancing okay. No aluminum. Chevy = 5.7” length maximum  rods. No floating pistons.
D. OEM cranks only. Steel or cast. Balancing okay. No splayed main caps. No after market cranks.
E. After market rod, main and head bolts or studs allowed. Push rods may be any length.
F. Stock or circle track pans allowed. No dry sumps. No gas ported pistons. No accu. sumps.
G. Fluid dampener harmonic balancers are allowed. No roller rod, main, or cam bearings.
H. Cast iron water pumps only, except Ford and Mopar may be aluminum. OEM type only. Mechanically belt driven only!
I. Stock OEM cast iron intake is required. No marine or Bowties. No after market. No tall intakes.
J. Ford may use aluminum, but no hi-rise or air under intake.
K. Mopar intake is same rule as Chevrolet.
L. No Brezinski, porting, polishing, acid dipping, or anything similar allowed. No hi-rise.
M. After market starters okay. Must mount in front of bellhousing.
N. Power steering pump and reservoir must be a one-piece unit. Must mount in front of engine.
O. Steel side engine mounts may be of the 45 degree style or stock style.
P. Engine mid-plate is allowed and may be aluminum.
Q. Any brand of air cleaner allowed.
R. 3.48 stroke maximum for Chevy. Balancing okay.
S. Engine displacement can be checked by pump even on protest.
T. Oil filters must attach at factory specs. No Oberg, etc.
U. Polydyne coating or similar allowed.

CAMS:
A. Hydraulic lift cams only. Maximum lift = 450”. This may be measured at the valve or 12” of vacuum at 1200 rpms. Timing or carburetor may not be altered at time of tech, if vacuum used. It is the tracks discretion as to which  way they want to check cam, even on the protest. Must have vacuum fitting in intakes. If track opts to use vacuum for tech, tech by vacuum will be final.
B. No hydraulic roller cam or lifters. No bronze bushings in the lifter bore or similar pieces. Up to four bronze bushings will be allowed in lifter bore for repair. Hydraulic lifters only! No solid cams or solid lifters allowed.
C. Anti-pump up lifters okay. No gear drives.
D. No reverse rotation cams or motors. OEM rotation only!
E. No vacuum cans of any type allowed.

HEADS:
A. No porting, acid dipping, or polishing allowed. Screw-in studs and guide plates are legal.
B. Stock diameter springs only for heads used. Stock type rocker arms. Any ratio. Ford rocker arms on Chevrolet okay.
C. Flat milling allowed. No angle milling.
D. Full roller rocker arms or roller tips are not allowed. No aluminum.
E. No aluminum or titanium components allowed. No carbon fiber parts anywhere.
F. Poly-locks are allowed. Heads may be cut 360 degrees under valves in bowl area only.
G. No stud girdles. 1, 2, 3, 4, or 5 angle valve jobs are legal.
H. No Jesel or other assemblies allowed.  No O-ringing block or heads.
I. Any breather/valve cover configuration/composition is allowed.
J. Due to Fords and Mopars having no cc rule, neither will Chevy’s

CHEVROLET: HEADS-GM
A. Only these casting numbers can be used:  997, 445, 882, 624, 441, 487, 993, 185. These are the last three digits and they are the only ones legal.
B. No valves larger than 1.94 intake or 1.50 exhaust. May remove smog clips inside exhaust ports.
C. No X-heads.

FORD: HEADS
A. Any cast iron head. OEM Ford heads only. Headers listed for Ford are the only headers that can be used. If the headers don’t fit the head you are using, head is illegal.
B. No Boss or after market heads of any kind.
C. No valves larger than 204 intake or 1.70 exhaust.

MOPAR: HEADS - PLYMOUTH, DODGE, CHRYSLER
A. Any cast iron head. OEM Mopar only. Headers listed for Mopar are the only headers that can be used. If the header doesn’t fit head you are using, head is illegal.
B. No after market heads of any kind.
C. No valves larger than 2.04 intake or 1.70 exhaust.
D. Mopar can use the rocker arm bars. OEM only. No roller tips.

ENGINE LOCATION:
A. Back of entire flange must be mounted at a minimum of 70" forward of the centerline of the rear axle.  This will be measured on the passenger side of the car.
B. Minimum engine height is 11" from the ground to the center of the crankshaft. This will be measured on the front of the crank shaft/pulley.

IGNITION:
A. All cars must have ignition switch clearly labeled.
B. Ignition switch must be located within reach when standing outside the car (easily accessible to emergency personnel.) 
C. Stock or stock style ignition only. Ford may use Motorcraft or FoMoCo, including box. Mopar may use Mopar, including box. HEI legal on Ford or Mopar.
D. HEI must remain in one unit, no external coils allowed, unless you are using dual or single point distributor.
E. MSD or any module may be used as long as it fits inside the distributor with no alteration. Vacuum advance may be removed and the pick-up coil locked.
F. MSD, any brand, or GM electronic boxes are not allowed. No magnetos.

BATTERY:
Only one 12 volt battery is allowed. Must be securely mounted.  Subject to tech inspection! Battery may be charged by an alternator.

EXHAUST SYSTEM:
Headers must be Schoenfeld #16100, 1-5/8” tubes with 3” collector for GM. #46100, #461W2, #462, #462W2 for Dodge. #361, #362, #562, #562-4B #563-4B for Ford. No modifications to headers of any type. No turn-outs. Please check with track for muffler rules.

RADIATOR:
Only one radiator is allowed.  It may be aluminum.  Radiator must be mounted in front of engine.  Maximum size: 27” X 19”. Racing radiator cap is allowed. Electric cooling fans are okay. May not have water outlets to spray on radiator.  Catch Cans Required.

FUEL:
Gasoline only. No oxygenated or other performance enhancers! No alcohol or nitrous.

FUEL PUMP:
No electric fuel pumps. Only stock mount push rod activated Holley and Carter style allowed. No bypass fuel systems, pressurized, or return lines allowed. No regulators of any type.

FUEL CELL:
A. Maximum 22 gallon fuel cell.
B. Fuel cell with a roll over valve is required. Must be securely mounted inside trunk area only, must be between frame rails, and must be totally enclosed from the driver compartment. A minimum of two (2) fuel cell straps required to secure fuel cell.
C. Fuel cell protection bar required. Must be a minimum of 1 1/2" X .095". It must protect the fuel cell from the rear. It must be as low as the fuel cell, and extend from side to side as wide as the fuel cell. It is recommended that this bar be attached to the frame, not the bumper. If the fuel cell protection bar is not present, the car will not be allowed to continue running.

CHASSIS

FRAME:
A. Frame cannot be cut, bent, or altered to change suspension brackets, except upper control arm brackets on front end.
B. Front frame horns can be cut off in front of the steering box and idler arm.
C. Rear frame rails may be cut off behind upper  shock mounts.
D. Replacement may be made with round, square, or rectangular tubing.
E. Front frame may be cut for radiator clearance.
F. Frame may be cut for seat clearance.
G. You cannot cut holes in frame to lighten it. Rust may be removed in front of lower rear trailing arms and cleaned up on body mount holes.
H. Frame cannot be widened, narrowed, shortened, or lengthened.
I. Cross member mounts on frame for transmission may be removed, but cannot be farther forward than welds on frame.
J. If weights are used for ballast, weights most be painted white and number of car must be on weight. No mercury ballast or any similar type of ballast may be used. All weight must be securely fastened. Loss of weight will be cause for disqualification.

ROLL CAGE:
A. Main roll cage must consist of continuous hoops not less than 1-1/2" X .095". All welds must be complete. No brazing or soldering. No part of main cage may extend forward past rear motor  plate. The main roll bar must not attach to the frame rearward of front edge of the rear tire.
B. Main roll bar and halo must be a minimum of 1" above the drivers helmet.
C. A minimum of three (3) driver's door bars, and two (2) passenger side door bars is required.
D. Four (4) bars, two per side, may extend from the main roll cage to the points on the main frame in front of the upper control arms. These bars may have two additional  braces per side to the main frame.
E. Six (6) bars may extend from the main cage to the rear, X-bracing is allowed.
F. Door plates will be mandatory in 2004.  At least 4" X 12".  
G. Cages must be steel or chrome-moly.
   
NERF BARS:
One single nerf bar between the front and rear wheels, on each side of the car is allowed.  Maximum size = 1-1/2" X .095". They are to be attached to the cage at the front and rear sections of the nerf bar. No center supports are allowed on the nerf bar.  Nerf bars may not be outside of tires. All bumpers and nerf bars must be capped.

WINDSHIELD BARS:
Minimum of three (3) windshield bars 5/16" in diameter is required. Must be mounted in front of driver.

TIRES:
The tire may be a DOT radial or bias tire with a manufacturer’s warranty. No mud or snow tires allowed. Any tire stamped with SIMS is allowed.  Hoosier "500" is optional tire.  SIMS can deem any tire legal or illegal at their discretion. Grooving is okay. Siping is not allowed. (This means by razor blade or anything similar.) "50" series  is largest DOT allowed.

WHEELS:
A. Only steel 15" X 8" or steel 14" X 8" wheels are allowed. RR beadlock is allowed.
B. No wheel spacers allowed with stock studs. Any offset wheel allowed. 5/8" studs are allowed. Wheel spacers may be aluminum.
C. One-inch diameter lug nuts are required.
D. Wheel adapters will be treated as spacers and may be aluminum. 1-1/2" inch maximum on spacers.

INTERIOR:
Oil and transmission fluid coolers are not allowed in driver’s compartment.

UPHOLSTERY:
A. No upholstery allowed, other than driver’s seat cover.
B. No plastic in driver’s compartment.

BODY:
A. All body measurements simplified:

• a) 23" maximum

• b) 40" maximum

• c) 67" minimum

• d) 31" minimum/48" maximum

• e) 98" minimum/121" maximum

• f) 41" maximum

• g) 58" maximum

• h) 28" maximum

• i) 55" minimum/67" maximum

• j) 77" maximum

• k) 31" maximum

• l.) 35" maximum

• m) 9" minimum/15" maximum

• n) 32"x32" minimum/53"x53" maximum

• o.) hood scoops optional

• p.) Do NOT add or subtract 3" from any of the above measurements (as was previously stated). That math has already been done for you, and the +/- 3" is now included in the above measurements.

B. Roof rear sail panels are allowed one 90 degree bend along the top edge of the sail panel, but must be less than 1” wide. Gremlin style roofs not allowed.
C. No more than 6" of total rake allowed on the body deck.  A maximum of 3" of rake (of the 6" total) is allowed in the door section and a maximum of 3" of rake is allowed in the quarter panel section. If you keep the door section level, then you are only allowed 3" of rake in the quarter panel section.
D. Minimum ride height is 5" from ground to side frame rails.
E. Plastic body panels and plastic filler panels are not allowed.
F. No convertibles, unless special race.
G. Cars must have full deck interior from one side of the body to the other. Decks must be aluminum or sheet metal.

FENDERS:
Quarter panels must be 90 degrees to the ground, with a maximum of a 45 degree bend 4" from the bottom of the doors and quarters and 2" on top.

FIREWALL:
Must be metal or aluminum with minimum sized holes for throttle, etc. Firewall must be sealed from engine compartment.

FLOOR:
Must be metal or aluminum. Must cover entire driver’s cockpit to front edge of seat.

BUMPERS:
A. Two (2) bar front bumper is mandatory.  Maximum size is = 1-1/2" X .095".
B. One single bar rear bumper is required.  Maximum size is = 1-3/4". The required fuel cell protection bar (maximum size = 1-1/2" X .095") may be attached to the rear bumper.

HOOD:
A. Must cover completely the  top of engine and radiator.
B. Must extend from the nose piece to the deck.
C. Hood may be made of metal, aluminum, or fiberglass.
D. Hood must provide a seal to the top of  the engine compartment.
E. Cannot cover side of engine more than 5".
F. Hood scoops okay.

SPOILER:
Rear spoiler is allowed, with a maximum use of material of 15", measured along the spoiler, from the deck to the top, not straight up and down.  A maximum of four braces are allowed, one on each side, measuring a maximum of the angled height of the spoiler x 24" long.  Only one spoiler is allowed.  Aluminum or Lexan okay.  Spoiler may not go beyond back bumper.

DRIVER RESTRAINT SYSTEM

SEAT:
Aluminum racing seats with right side rib protection is required.  A seat that provides both left and right side rib protection is recommended.  Seat must be securely mounted.  The racing seat must be bolted to a reinforced cross member and bracket(s).  This cross member must be welded to the roll cage, not just the floorboard. The back of the seat must be supported and bolted to a flange that is connected to the cage.

SEAT BELTS:
Racing type 5 point seatbelts are mandatory. Must be approved 3" wide shoulder straps, lap belts and a minimum of one 2" sub strap. All belt systems must be securely attached to the roll cage, or seat cross member and not to the floorboard. Seat belts must be in good condition.

WINDOW NETS:
Window nets are mandatory.  It may be mesh or web style.  Sprint car cage net is allowed. A quick release window net system must be used.

HELMET:
Must be an approved racing helmet in good condition. At track discretion.

PROTECTIVE CLOTHING:
Driver suit (fire suit) mandatory, may be one (1) or two (2) piece, must be complete and be of fire resistant material and in good safe condition. Fire resistant driving gloves recommended. Shoes optional.

CLAIM:
Only SIMS-registered drivers may make a claim.

SIMS CLAIM RULE:
A. A $500 & SWAP engine claimer is in effect. This claim includes intake (not adapter/spacer or fittings) to the oil pan, from the back of the block (not flywheel, converter, clutch, pressure plate or distributor) to the water pump (not pulleys, belts, power steering unit, fan or fuel pump), from head to head (not valve covers, carburetor, air cleaner, headers, starter, oil pan, spark plug wires, or spark plugs).
B. The official claiming area is the flag stand, or wherever track designates.
C. Claim must be made immediately after the "A" main race finishes (checkered flag).
D. Engine must be completely removed within one (1) hour from time claim is made and driver agrees to sell.
E. Only the driver may make the claim.  Driver must have money, SIMS claim form, and current SIMS registration card in hand (cash only).
F. The claiming driver must be on the same lap as the driver being claimed.
G. Only the top two cars may be claimed.
H. Who can claim:

• On opening night of the race season, all drivers are eligible to claim as long as they ran 50% of the races at said track the previous year and all can be claimed.

• On the second night of racing, only drivers that raced the previous night of racing are eligible to claim.

• On the third night of racing, only drivers that raced the previous two nights are eligible to claim.

• During the remainder of the season, the driver making the claim must have raced at this race track the previous three (3) nights of racing.

I. Drivers may only claim two (2) engines per race season, or one more than he has been claimed. 
J. A driver can claim another driver’s engine only once during the year.
K. In the case of multiple claims on the same engine, draw will be held with claiming drivers to determine who gets claim. 
L. Refusal to sell forfeits all cash, trophies, and points for the season.  If claim is refused, claim is not held  against driver.

• Driver refusing to sell his or her engine the first time is fined $500.00.   

• Driver refusing to sell their engine the second time is fined $750.00, and suspended for one week.  

• Driver refusing to sell his or her engine the third time is fined $1000.00 and suspended for three (3) weeks.  

• Driver refusing to sell for the fourth time will be suspended for the remainder of the season, and will not be allowed back until a $2000.00 fine is paid.
  

INFRACTION OF ANY RULES STATED IN THIS BOOK WILL RESULT IN LOSS OF POINTS, MONEY, AND AWARDS FOR THE NIGHT. DON’T COME BACK UNTIL YOUR CAR IS LEGAL. And remember . . . IF IT DOESN'T SAY YOU CAN, DON'T DO IT!!! Clarifications of rules can be made by SIMS AT ANY TIME!!! If you have any rules questions, please call Sims at 325-721-8800.

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