upcoming races
Las Vegas
St. Louis

LAS VEGAS // Nov 21-24, 2019

ST. LOUIS // August 1-3 2019


class rules/ St. Louis Mickey Thompson 275 Radial

X275 is a 1/8-Mile Heads-Up Class run on a .400 Pro Tree / "All-Run Qualified Field"
on a Pro Ladder and Auto-Start is in effect.




The car must retain its original appearance, profiles, and dimensions. Factory roof and quarter panels must be used. 2005 and newer vehicles permitted replacement roof panel. Factory firewall must be in factory location, notching/smoothing permitted but must be identifiable as stock location. Aftermarket fiberglass and/or carbon fiber replacement panels are limited to hood, front fenders, doors, deck-lids, and bumpers only. All front ends must be of factory dimensions and cannot be lengthened and must meet all NHRA/IHRA height. (See ground clearance note below). Any beam tripping devices forward of the bumper are prohibited. (Track tech official will have final say) Aftermarket wings and spoilers are permitted. Complete stock appearing front and rear bumpers are required. A hood must be used: scoop or hood must cover the entire induction system. Forward facing hood scoops/ turbo or supercharger inlets are permitted.



Minimum 3 inches from front of car to 12 inches behind centerline of front axle, 2 inches for remainder of car, except oil pan, oil retention device, and headers.



Factory appearing dashboard, door panels, and driver seat is required. Carpet is required on floorboard. Factory floor pan on driver and passenger side required from factory firewall to rear of door jamb. Transmission tunnel maybe removable and must be metal. Double frame rail permitted. Aftermarket steering column is permitted.



OEM glass or Lexan windows are permitted.



Complete stock chassis and frame rails must be retained from motor plate/shock tower to behind the rear wheel opening. Back-halved cars are not permitted. Front core support may be modified or removed. Aftermarket bolt-on replacement front K-members/sub frames are allowed (if front shocks bolt to K-member then they must be in factory location, only Chevy II or Dart permitted strut conversion). Shock tower can be notched or trimmed but must be in factory location, verifiable by the factory sheet metal being retained between frame rail and top of tower. Mini tubs are allowed. Rear frame rails may be notched for clearance and must be in the factory location. Factory wheelbase must be maintained. (+ or – 1 inch)



Maximum displacement for all engines is listed below. Small blocks nos are allowed any deck height but must retain stock bore spacing. Big block allowed the following deck heights but must retain stock bore spacing. GM Big Blocks are limited to a 10.2 deck height. Ford Big Blocks are limited to a 10.3 deck height. Mopar Big Blocks are limited to a 10.7 deck height. (Cylinder head specs and list for BB Nitrous Combos attached)(Billet SB/BB blocks permitted with cast head only and +50 lbs.)



Single turbocharger limited to 88 mm maximum. (Garrett GTX55-88, Exile ETR-88, or = Forced Induction, Comp, Bullseye - mid frame or current (2013) Gen II Pro Mod MF88, PTE LF85 or LF88 turbos only). GARRET GTX GEN II Permitted. Turbocharger size will be verified by measuring the housing bore at the leading edge of the impeller wheel and must maintain the contour of the compressor housing. (Stepped or Clipped compressor wheel prohibited) Inducer dimensions will not exceed 3.462 inches and Exducer dimensions will not exceed 4.765 inches on MID FRAME turbos. Inducer dimensions will not exceed 3.462 inches and Exducer dimensions will not exceed 5.56 inches on LARGE FRAME turbos. The maximum diameter of the housing bore at the leading edge of the wheel may not exceed 2 mm more than the maximum allowable turbocharger size permitted. Inserts or reducers to achieve inlet or outlet dimensions prohibited. Any type of air to air or water to air intercooler permitted. Turbochargers w/nitrous-oxide prohibited except on 2-rotor, 4 cylinder, and inline 6 cylinder engines.



Cog or gear driven superchargers are permitted, must meet all factory inlet, outlet, and internal housing dimensions. Inserts or reducers to achieve inlet or outlet dimensions prohibited. Any type intercooler is permitted. Supercharger cannot be combined with nitrous oxide. Roots superchargers are limited to the 8-71. Centrifugal superchargers are permitted. Screw superchargers are not permitted.



Small block is permitted to run any type multi-stage nitrous systems. Big blocks are limited to a single stage fogger (2 nitrous solenoids, no limit on fuel solenoids) and two bottles are permitted or if using a single plate then your limited to (1 fuel solenoid, 1 nitrous solenoid), and 1 purge solenoid, purge must exit engine compartment. Big Block & Small block nitrous are permitted water injection. All EFI Big Blocks will only be allowed 2 nitrous solenoids for a dry nitrous system and will only have 1 line per nozzle/per cylinder. (Using both sides of the fogger nozzle on a dry EFI NOS BB combo are permitted)(Cold nitrous systems permitted on big block combo and permitted on small block combo) All lines on big block combo must be visible and continuous from bottle to wye without interruption.



Any factory style automatic transmission allowed. OEM factory style manual transmission allowed. Bruno-Lenco transmissions are prohibited. Aftermarket clutch-less manual transmission and clutch assisted manual transmissions are permitted on naturally aspirated SB & BB and nitrous small block combinations only. Electric shifters or air shifters are permitted. Must not touch firewall or be mounted to firewall. Mid-plate permitted. Roots Blown Combo not allowed lock up style transmission.



Small Block combinations may run any type induction. Big Block Nitrous combinations are limited to a dedicated single opening cast intake or cast tunnel ram with a single carb or a single 4150 or 4500 series throttle body. (4 blade, dual blade or single blade throttle body permitted). Big Block N/a can run any style intake and carb/TB combo.



Dry sump oiling systems are permitted on all cars



Mufflers or inserts are required on all cars except for turbo cars. Exhaust may exit underneath car or out the front fenders but must not affect timing or staging beams.



Gasoline/Alcohol/E85 permitted on all applications. Weights are based on gasoline (including E85) as the fuel. Any use of M1 will incur a 50 pound weight add. M1 used in addition to an intercooler is NOT permitted. Water injection permitted on SB/BB NOS combos only.



Functional headlights, taillights and brake lights required. All headlights, brake lights, etc. must be on car and not removed for any reason. All vehicles may be towed back from their passes.



Stock style or ladder bar suspension cars only, stock rear frame rail must be permanently attached and in the stock type location. Aftermarket direct replacement components such as: front control arms, rear control arms, front coil over shocks, and rear coil over shocks are permitted. Aftermarket rack and pinion steering allowed. Rear leaf springs, springs, shocks, and coil-overs may be moved to accommodate tire clearance, and do not need to be mounted in stock location. Bolt-on or welded sub-frame connectors, rear sway bars, are permitted on all cars. Wheelie bars are prohibited on all cars. Torque arms are only permitted on cars that were originally equipped from factory with it. (See notes below) Upper and Lower control arms must be mounted in the factory style chassis locations -S Box permitted.

** Late model GTO and 5th gen Camaro permitted bolt in torque arm style suspension

**Late model Mustang (Cobra Jet style), Camaro (COPO), and Mopar Drag Pak permitted on their respective body type.



All cars with power adder must compete on a Drag Radial type tire with the following sidewall designation 275/60/15 or 28 x 10.5 Pro Bracket Radial. Naturally aspirated combos are permitted to run a 28.0” x 10.5” slick, no “W” tires permitted.



6 Cylinder diesel (Cummins) Turbo 88mm 3200

6 Cylinder/4 Cylinder 88 mm 2750 (nos permitted)

Small Block Nitrous max 500 cu in. 2550

Small Block Supercharger max 480 cu in 4.00/4.125”(F1R/Xi) Inducer 2725

Small Block Supercharger max 480 cu in 4.200” (F1X/XB105)Inducer 3050

Small Block Supercharged max 480 cu in 871 2750

Small Block Turbo max 480 cu in 80mm x 130mm 2900

Small Block Turbo 480 cu in 85mm 3100

Small Block Turbo 480 cu in 88mm 3150

Big Block Naturally Aspirated 750 cu inch 2600

Big Block Conventional Head Nitrous up to 588 2950

Big Block Conventional Head Nitrous up to 632 3100


Big Block Conventional Head Roots up to 632 3500

Turbo weights based on Gen II PTE Pro Mod Series and Gen II GTX Series with maximum compressor exducer of 133 mm (LF85/88 fall into this weight)

Add 50 lbs. for billet head (must be used with cast block only of stock bore space/deck height)

Add 50 lbs. on boosted combo for M1 (intercooler not permitted with use of M1 as primary/only fuel)

Add 50 lbs. for billet block (must be used with cast head only and be stock bore space/deck height *except mod motor)

Add 50 lbs. for lock up converter/trans

Add 50 lbs. for SR20 or equivalent BB cylinder head must maintain 20* Valve Angle and conventional port layout

Deduct 75 lbs. Stock Valve Angle (23GM/20FORD/18MOPAR/15 LS)

Deduct 50 lbs. Stock Valve Angle RR (23GM/20FORD/12 LS)

Deduct 50 lbs. F1C-10.5(from 4.00 base wt)

Deduct 100 lbs. F1A-104(from 4.200 base weight)

Deduct 50 lbs. 4150 carb/throttle body

Deduct 100 lbs. GTX55-85 GTX55-88 GEN 1 (118 mm compressor exducer)

Deduct 100 lbs. plate nitrous system

Deduct 200 lbs. for 8.2 deck or mod motor (*if mod motor billet block used deduct is only 100 lbs.)

If one combination appears to have an advantage rules may be changed at the race director’s discretion at ANYTIME in order to keep a level playing field for all competitors.


SCSN ST LOUIS REQUIRED DECALS (Decals will be available during registration at the SCSN Event Trailer)





"Mickey Thompson" decal must be installed on base of windshield on the passenger side.

(Bottom left hand side when looking at front of vehicle windshield)





"Unlimited Products" Decal must be placed on either left or right side of race car in a highly visible location on the rear ¼ Window, ¼ panel or wing




"PSCA" Decal must be placed on both left & right sides of race car in a highly visible location on the rear ¼ Window, ¼ panel or wing




All contingency decals may appear anywhere on the vehicle in a clear and organized fashion. Contingency decals may not be overlapped or modified. Most decals are available at the SCSN Event Trailer, but in the event the SCSN does not have the decals in stock, it is the racer's responsibility to obtain the proper decals to be eligible for the Contingency payout.







X275 is an all run qualified field on a NHRA Pro-Ladder



All X275 entries can tow to staging lanes and to the track scales with a golf cart or other similar small tow vehicle. All carts will be subject to search by a SCSN Official at any time.



Each X275 driver must alternate lanes during qualifying. If you choose to ignore this rule, your second consecutive pass in the same lane on the same day will be disqualified.



The Auto-Start System will be turned on with a 7-sec timeout




All vehicles must take the tree, and run down the 1/8th mile


Once Your Vehicle Passes Tech Inspection, There Are No Refunds!!!



$4,000 / To Win

$1,000 / Runner-up

$500 / Semi's

Class & Racer Entry Fee: $200




Heather Roth: Event Coordinator


Call/Text 1-702-701-6464


Mel Roth: President


Call/Text 1-661-917-3078



All rules subject to change at the sole discretion of the SCSN Technical Services Department.