1) Stock appearing bodies; 6.5” maximum spoiler height; 4” minimum ride height
A) No downforce bodies or panels, No side boards, No wicker bills
2) Minimum roof height is 47” measured from top of windshield 10” back.
3) Tread width - Coil-over - 66” • Big spring - 66”. Fabricated big spring cars with big springs front and rear will have out board mounted shocks. Stock stub cars will have big springs both front and rear, and the front springs will be in stock location. Big spring means 4-3/4” min. diameter, front & rear.
4) Minimum wheelbase = 101”
5) Minimum weight = 2900 lbs., See 8 & 9 for tour and crate weights • Maximum left 58% all cars
A) If necessary, MTRWP officials may add or subtract weight to ensure fair competition
6) Maximum cu. inch = 360 (Ford, Chevy) • Chrysler = 365 cu. inch
7) Cast iron cylinder heads only: (Exception - see rule #7-I for Brodix spec head rules)
A) Maximum cylinder head intake ports 215 C.C.
B) Over 215 C.C. = Add 100 lbs.
C) No porting, polishing or grinding of any kind on cylinder head or intake.
D) Port matching is allowed up to 5/8” on the intake manifold only.
E) Any 4BBL carburetor, see rule #8-D for tour motor carb, see rule #9-A & B for crate carburetor option
F) Any compression
G) Minimum crank height of 10” • Dry sumps approved
I) BRODIX SPEC HEAD RULES
i1) Only part numbers - Brodix SP - CH / FO / MO - will be allowed
i2) All Spec heads will be supplied with CNC bowl blend and intake port matching.
i3) No grinding or blending of CNC work is allowed.
i4) No grinding or polishing of any kind is allowed anywhere on the castings.
i5) No use of any substance that may change or alter the shape or the size of ports or combustion chambers is allowed.
i6) A maximum valve size of 2.080 intake and 1.600 exhaust will be allowed for all Spec heads.
i7) Valve seats and guides are to remain as manufactured and in their cast positions.
i8) Valve angles are to remain as manufactured. The original seat center locations as provided by the head manufacturer may not be altered.
i9) No tapering or re-shaping of valve guides will be allowed.
i10) No titanium springs, steel only.
i11) Titanium valves approved.
i12) Cylinder heads may not be angle-milled. A minimum combustion chamber volume will be 60 cc.
i13) Minimum valve stem diameter is 11/32”.
i14) Spec cylinder head serial numbers must remain on the head and may not be defaced or altered.
i15) No welding modifications are allowed to the original head castings.
i16) May only be used on motors 360cid of less.
8) TOUR MOTOR – TOUR 9 to 1 ENGINES: Minimum weight = 2900 lbs. with approved 390 carb
A) No aluminum blocks. Aluminum heads of OEM designs only. Only 23-degree heads allowed on GM products. No SB2 heads, SM splayed heads, 14 degree or Buick heads allowed.
B) Any crankshaft (no titanium), camshaft and camshaft drive allowed. Compression ratio maximum allowed is 9:5:1 on all cylinders for Tour
engines with roller camshaft.
C) Intake manifold: Any approved high-rise intake manifold allowed. One aluminum adapter (spacer), maximum of 1” TOTAL thickness allowed Only 2 gaskets allowed with a maximum thickness of .050”. Spacer must be straight cut with no taper.
D) Carburetor: Holley 390 CFM list #6895 or #80507. Carburetor boosters may be modified in the following manner: Booster bars may be removed, booster length minimum of .700”. Inside booster diameter maximum of .480”. Boosters may be tapered from center seam down. Boosters may not be relocated.
9) CRATE MOTOR - Must meet Montana Raceway Park 2011 crate motor rule specs. Must contact the speedway office for additional details.
A) GM 604 with any 4bbl carburetor = 2900 lbs.
B) GM 604 with box stock 650 Holley carburetor #4777 or #80541-1 = 2850 lbs.
10) Maximum 10” wide steel wheels
11) No alcohol or nitro engines • No antifreeze
12) Must qualify, start, and finish, on tires purchased only at Montana Raceway Park.
13) NO TIRE SOFTENING
14) No Traction Control Systems of any kind.
15) No electronic recording devices allowed in or on the car (data loggers, cameras etc.)
16) Two-way radio communication between driver and minimum of one spotter for each team is required for all competitors.
17) First 3 finishers will have engines checked for size and other related components of these rules, which will be left up to the discretion of the technical director.
Driver and Pit Crew Conduct Rules:
The driver of the car is responsible for the crew, friends, and family with them. Any person or persons involved in fighting, improper language, or any misconduct while at Montana Raceway Park may be subject to fines and or expulsion. This is designed as a upper level event and all teams must maintain professional attitude and conduct. Decisions on the interpretation of the rules specifications and conduct will be decided by Montana Raceway Park and the Tech Officials. The Promoter, Race Director, Chief Technical Inspector, or promoters authorized agent shall be empowered to permit minor deviations from any of the specifications herein or impose further restrictions that, in his/her opinion, do not alter the minimum acceptable requirements.
Car numbers and pit pads will be assigned with paid entry • No duplicate or “X” Numbers For more information regarding these rules please give us a call 406-257-7223