2017 Sportmod (B Mod) Rules
Printable Copy: 2017 SPORTMOD (B-Mod) RULES
1. 1964 or newer OEM perimeter American rear-wheeled passenger car
frame only. No sports car frame. No convertible or station wagon. No stub
2. Frame must be full and complete, cannot be widened or narrowed and
must be able to support roll cage on both sides. Exceptions are weight jack
in original line of spring tower, frame may be cut a max of36 inches forward
from center of rear end housing. Horns may be removed in front of steering
box and notched maximum of1 inch at bottom for tie rod clearance.
Maximum 7 inch wide opening in side of spring tower for spring removal.
3. All cars must have box type roll cage of at least 1.5” O.D tubing .095
minimum thickness. All cars must be equipped with a minimum of three
protective bars inside each door. Halo loop MUST be a SINGLE bar.
4. Must have loop to protect fuel cell.
5. Minimum wheelbase 108” maximum 112” both sides.
6. No part of car can be lower than 4 inches from ground except front
7. Floorboard must be steel or 16 gauge aluminum
8. Drivers windshield opening must have a minimum of3 upright bars
of3/8” gauge steel rod welded to roll cage in front ofdriver 6” apart.
Windshield opening covered by wire mesh is strongly recommended. Door
window openings must be minimum of 12”
9. Bumpers must not be wider than outside of the frame. Must run
modified style bumper, all bumpers must be securely bolted or welded. All
bumpers and nerf bar ends must be capped, door nerf bars 1.25” max tubing.
1. Two options
a) Aftermarket three link (Must be steal, all mounts and brackets
must be welded or bolted solid) No swing arms, pull bar must
mounted within 6” of center of housing. May mount rear spring
directly over housing or use coil over eliminators (sliders). Lower
spring perch or coil over mount must be welded or bolted solid to
rear end housing. Birdcages must be locked.
b) Multi-leaf spring design (Must be steal, all mounts and brackets
must be welded or bolted solid) Lead spring must use steel multi leaf
springs with no additional suspension components beside one shock
per wheel. Adjustable lowering blocks allowed. No coil springs can
be used with lead springs.
2. Stock unaltered or tubular lower arms allowed. Must be in stock
location (location per make) Must be Chevy-Chevy, Ford-Ford. Monoballs
allowed. Only modifications are to allow screw in lower ball joints and alter
so lower control arms don hit hub.
3. Five lug stock spindles, no fabricated spindles
4. Weight jacks may be used, screw type only, cannot be adjusted from
5. Upper pull bar must be solid and within 1 inch of center line rear end
6. All J bars and pan hard bars must be mounted from left side of frame
to right side of rear end or vice versa and must be solid mount
7. 72” from center of rear end to mid-plate
8. Tubular upper “A” frames allowed. Swedge tubes are allowed.
Can run heims on uppers
1. 360 C.I max, factor OEM blocks only. Can mix match frames motors
2. NO 400 C.I blocks
3. After market or stock steel heads are allowed. No aluminum heads,
must be stock valve angle Chevy 23* ford 22*
4. Aluminum one piece sand cast intakes allowed
5. 1.5 Chevy or 1.6 Ford ratio rocker arms. No shaft rockers. Stud girdles
6. Any distributor allowed. No mag or crank trigger. MSD allowed
7. Stock journal size 3.48 stroke Chevy
8. Any steel oil pan allowed. No dry sumps. Inspection plug
recommended in oil pan. If no inspection plug you may be required to
remove the oil pan.
9. Oil cooler allowed
10. 602 Chevy crate engines allowed. Motors and carburetors CAN be
claimed, traded, and or teched at any time by promoter and or rule committee.
Factory hei distributor, MSD. If motor is caught illegal YOU MUST run 2
barrel carb for remainder of season.
11. NO ROLLER CAMS
FUEL AND CARB
1. One (1) four (4) barrel 650 cfm unaltered Holley Carburetor, art
number 4777 r 80777 or Holey HP Carb part number 80541-1, (-2) will be
permitted. Built motors must run (2) barrel unaltered cfm Holley carb part 4412. One (1) two (2) barrel unaltered cfm Holley carb part 4412 will be permitted. All carb components must remain unaltered. Any changes will
result in disqualification for the event. Any alterations to the carb will not be
permitted. Removal of choke assembly and air horn only. Must pass gauge
2. Air cleaner max height from air horn base 5”
3. 2” carb spacer, 1 spacer only
4. Racing gas or pump gas only. No alcohol, nitrous oxide, propylene
oxide, nitro methane, or additives.
5. Fuel cell required. Must be contained in an approved container. Fuel
cell not to be mounted lower than center of rear axle, with minimum two
straps 1/8” x 2”
6. Belt driven fuel pump only when block is not machined for
CLUTCH AND TRANSMISSIONS
1. Transmission must have 2 forward gears and a working reverse. Must
have functional clutch. No in and out boxes
2. Bert type transmissions allowed
3. Starter must be in stock location
4. Blow proof bell housings required. Automatic transmissions must run
explosion proof blanket or 1/4” steel scatter shield over converter
5. All cars are required to have a drive shaft loop 12” from end of
6. All drive shafts are to be painted white. No aluminum or carbon fiber
1. Any steel approved OEM passenger car or truck non cambered rear
end allowed. Must be centered in chassis.
2. All components must be steel except lowering blocks, axle cap, and
3. Safety hubs (floaters) allowed
4. Quick change allowed. The ring and pinion on a quick change must be
5. Inspection hole in housing required
6. Center section and yoke cannot be lightened. Full spools and mini
spools only (no type of lockers allowed) No aluminum 3rd allowed. No
offset ring and pinions
7. Solid steel and one piece drive flange only
WHEELS AND TIRES
1. Maximum 8” wide wheels. Bead locks are optional on right side only.
Outside covers optional on all four tires.
2. Must be EMOD 26.5 or 27.5 A, AS, H, or American racer
3. 9/16” or 5/8” wheel studs must be used on right side
4. Tires may be sipped. Front tires may be grooved. Rear tires may be
5. Tires must pass durometer within manufacturer specs. Tires may be
checked at any time.
SHOCKS AND SPRINGS
1. One steel, non-adjustable, unaltered shock per wheel only. All shocks
must completely collapse at any time. No external or internal bumpers or
stops. No bulb type, AGR, or remote reservoir shocks. No Schrader valves or
bladder type valves allowed. No inerter, J-damper shocks, active mass
damper chocks and or through-rod-design shocks allowed. Rules committee
reserves the right to allow or disallow any shocks at their discretion. It is the
responsibility of the racer to receive approval for any questionable shocks
used in competition. $150 claim per shock and will be offered for resale.
Minimum 4.5” springs only. No progressive springs allowed.
2. One shock and spring per wheel
1. B-Mod weight 2,400lbs for crate or 2,400 for open motors MIN.
2. Lead must be painted white and mounted with a minimum of two
1/2” bolts. Lead may not be inside the driver compartment or outside the
1. Minimum three-wheel brakes. Brake adjusters are allowed inside the
car. Dual master cylinders allowed.
2. Aluminum brake calipers not allowed
1. Nose no wider than frame horns
2. UMP body rules apply
3. No side boards, sails must attach to roof, no spoilers. Both sails must
4. There must be an 18” number on each door and the roof. All numbers
and letters must be easily visible and readable by the track officials. In the
situation of duplicate numbers the track officials may assign a letter to you.
It is your responsibility to add this letter to your car on the roof, driver’s side
and passenger side. Failure to do so will cause you to be scored last for your
1. One OEM style battery allowed. 14”x8” maximum. 16v batteries are
allowed. Must be mounted with a 3/8” rod and be mounted behind fire
shield and out of driver’s compartment.
2. A switch to disable all power to car must be installed behind driver
within reach of safety man at shoulder height and must be clearly marked
1. All cars must have a sturdy seat belt and safety harness, three inch
seat belts required. Must be 5 years or newer and date on tag must be visible
2. Five point safety belts and flame resistant racing suits required
3. Gloves recommended
4. All drivers must have an approved racing helmet
5. Window net recommended
6. Head and neck restraint systems highly recommended
7. If you do not have a full containment seat you must run a window net
WISSOTA RULES (for their cars)
IMCA RULES (for their cars)
USRA RULES (for their cars)
Weight can be 2,400lbs
No weight needed in front for transmissions
Can run Hoosier tires. NO D tires
Can run roller rockers
If it doesn’t say you can do it, it is not legal! Rules may be amended or
changed as necessary throughout the season. It is the responsibility of all
participants to know the rules.
Situations not covered in any of these rules will be handled at the discretion
of the track officials as they arise. Decisions of track officials are FINAL!!!