WPI/NTPA Competition and Safety Rules to Be Implemented in 2024

The following rules were approved by the WPI/NTPA Joint Executive Board on Friday, September 15, 2023.

2024 NTPA Pulling Rules – NEW RULES!!

Additions and corrections effective for 2024 season

Light Limited Super Stock

  • Besides corrections to 2023 rules for LLSS previously posted to NTPA Tech Page in early 2023, the following rule was adopted
  • Light Limited Super Stock – limit all diesel engines to 3.4 x 4-inch smooth bore turbo including those engine sizes that allow two turbos. Use of a 3.0 x 4-inch turbo with MAP ring is no longer allowed

Pro Stock – 5.0

  • Approved PS 5.0 for competition at Regional National level (no longer on trial basis)
  • Removed Wimer as only supplier of PS 5.0 turbocharger to this class. Retained the same turbocharger size limits as stated in 2023 rule book

Hot Farm

  • Engine cylinder head must be OEM style (recast cylinder heads allowed). OEM stock dimensions (ie height, width, and length) must be retained. No billet heads allowed

Pro Farm

  • Amend current rule to require turbo intake and exhaust wheels to enter the 3-inch smooth bore restriction by 1/8-inch, same as required of other restricted turbochargers

Diesel Super Stock

  • Engines using a steel oil pan are exempt from pressure burst / relief device requirement in Diesel Super Stock division once final device type and specs are implemented

Modified Mini

  • Front skid plate to be configured according to dimensions and drawings as follows:
    • Skid plate must be made from 1/8-inch steel and extend across under front of chassis – rail to rail and solidly attached
    • Skid plate formed at 90 degrees with a minimum 2.500-inch radius at bottom front of skid
    • Tow hitch placed minimum 7.500 inches from ground
    • Skid to extend rearward to center of front axle
    • Bottom of skid plate to be bellow bottom of front rim
  • Driver’s feet must be placed inside the main frame rails while competing under green flag in Mini division at all levels


  • Rear weight boxes behind hook point must have a minimum 7-inch wide, open space centered behind the hook point so sled chain can be hooked into drawbar without interference from weight boxes

GN Modified – Turbine Engines

  • Allow turbine engines up to a combined maximum 9,450 horsepower as rated in NTPA Pulling Rules

Light Super Stock

  • Maximum weight limit increased to 6,300 lbs.
  • Request to increase weight made by division committee in 2022
  • No action taken due to SFI 47.2 Rollcage spec limited to 6,000 lbs.
  • SFI 47.2 Rollcage spec updated to 6,300 lbs. in July, 2023 now allows weight increase

Light Pro Stock

  • Approved proposal as submitted by committee
    • Limit turbocharger intake compressor wheel opening to 5 inches and retain existing 4.500-inch exhaust wheel limit – wheels must protrude in restricted openings by minimum 1/8-inch
    • No recast aftermarket injection pump housings. OEM P7100 or P3000 housings only
    • Retain current maximum of 48 lug tire rule – no Mitas tires
    • Lock in rules for Light Pro Stock class for 3 years
    • Follow all other class rules as currently written

Pro Street Diesel 4X4 Trucks – 2.6 turbo

  • Pro Street Diesel 4X4 Truck – 2.6 turbo class accepted as a Regional National division based on rules submitted by WTPA
  • Adjustments to safety related rules may be necessary to align with existing Diesel 4X4 requirements

Tires – Semi

  • Add the following rule omitted from 2023 NTPA Pulling Rules
  • Limited to standard 8.250-inch maximum rim width. No chains or cables permitted. No cutting of tires permitted.

Tires – Mini

  • All tires in division, at all levels, limited to maximum 17.5-inch tread width and maximum 30 lugs after cutting as tire is used in competition

Tires – General

  • Existing specs and procedures used by Technical Services to measure tires out-of-mold will remain in effect for all tire sizes listed in NTPA Pulling Rules
  • Approved Tech Services to establish specs and measuring procedure for tire width and circumference in ready-to-pull condition on vehicles at the track

Points / Competition

  • A. Points – pg.20 – amend 4. vehicle license level
    • Purpose is to eliminate disruption to division points chase
    • System (not finalized) to be implemented to limit negative impact to those chasing a points championship at GN level where entries exceed 25 or more in a division
    • Group GN points competitors to minimize negative effect from changes in track conditions
    • Divisions affected most – TWD, FWD, MINI, and PS
    • Procedure will be adopted to begin the first GN points event(s) after Chapel Hill, TN

Entry Procedures

  • Approved to limit all divisions of competition from jumping up more than one level at GN/SN events.
  • Example: PS 4.1 can register to compete in RN PS 5.0 competition but not GN Heavy Pro Stock

Contest Procedures

  • Kill Switch
    • Amend existing rule in 2. Contest Procedures – pg.30 – f.
    • While under green flag conditions, if kill switch is inadvertently pulled by sled cable (ie. cable caught in chain), and plastic tie is broken, competitor may be granted, at the discretion of the head official, to drop to last and have up to six (6) minutes to repair or replace failed or damaged kill switch and make another attempt.
    • Kill switch operation must be confirmed by a NTPA Tech Official before another attempt is made.
    • If incident occurs during first pull attempt, competitor will be granted two (2) attempts to make a measurable pull.


  • Turbocharger Exhaust Wheel Cage
    • Technical Services is evaluating wheel cage designs from turbo manufacturers.
    • Exhaust wheel cages submitted by turbo manufacturers will be sent to SFI for testing
    • Containment device between intake compressor wheel and guillotine will also be studied
    • Recommendations will be used to craft new rules necessary to ensure turbo safety for 2024 season
  • SSFWD Trucks
    • All trucks competing in SS FWD division only are required to use a SFI certified steel or titanium bellhousing
    • No aluminum bellhousings allowed in this division.

Bellhousing Certification

  • Adopted for 2024 – per 2023 NTPA Pulling Rules – pg.40 d. Bellhousing Certification / Renewal
    • 1) All divisions, SFI 6.3 aluminum bellhousings must display a valid and current SFI sticker from the manufacturer before being allowed to compete in any NTPA sanctioned event. This applies to all aluminum bellhousings in divisions where use is permitted.
    • 2) Starting Jan.1, 2024, all SFI bellhousings regardless of material (ie. steel, titanium, or aluminum) must display a current SFI certification sticker with an expiration date affixed by the manufacture. Any bellhousing previously stamped with a NTPA shield stamp will no longer be acceptable as a replacement for the SFI decal after Jan.1, 2024.
  • SFI 6.4 Puller and Diesel Drag Racing Spec Approved
    • NEW SFI 6.4 bellhousing spec approved by SFI Board of Directors in July 2023, spec is now available for manufactures to implement
    • 5-year certification for steel and titanium bellhousings available – aluminum not included
    • SFI 6.4 is applied at manufacturers discretion
    • Current SFI 6.3 steel or titanium bellhousings will meet SFI 6.4 spec
    • Pullers can request bellhousing manufacturer apply the SFI 6.4 – 5-year certification to a SFI 6.3 steel or titanium bellhousing

Definitions – pg.45 – d. Cubic Inch Formula

  • Approved the addition of + or – 1% cubic inch measuring tolerance to this rule to cover all engines in all divisions

Exhaust Headers – pg.58 – a. General Requirements – 2)

  • Approved standard 8-inch dimension from bottom of bend to top of header pipe in all divisions
  • Exceptions currently found in TWD and FWD will be removed.

5pt. Harness

  • Approved any application where a 5pt. harness is required, the harness must meet SFI 16.1 and such SFI identification tag must be affixed to harness.

About the National Tractor Pullers Association

The NTPA is the sport’s oldest and most respected truck and tractor pulling sanctioning organization. Governed by a board of directors, the NTPA is managed by World Pulling International (WPI), an independently owned entity. Headquartered in Columbus, Ohio, the NTPA provides rules and regulations and the infrastructures required for organizations throughout the country to arrange truck and tractor pulls.

The 2024 NTPA Championship Pulling Circuit is sponsored in part by Case IH, Beck’s Hybrids, WIX Filters, Hot Shot’s Secret, Enderle Fuel Injection, MAC Trailer, O’Reilly Auto Parts, Cow Tales, Mitas Tires, Cen-Pe-Co Lubricants, Ag Protect 1, U.S. Army, and STOP-FYRE.

Grand National Divisional Sponsors include New Fields Ag (Super Stock Diesel), Hi Torque (Super Farm), Yoder Popcorn (Pro Stock), CM Pulling Tires (Two Wheel Drive), Doctor Preload (Super Semi), and GMS Manufacturing & Machine (Light Modified). Region III is sponsorted by TerraMax. Region IV is sponsored by Pro Puller Tires. Point fund sponsors include the National Tractor Pulling Championships in Bowling Green, Ohio; the Budweiser Dairyland Super Nationals in Tomah, Wisconsin; Heritage Iron Magazine; Midwest Wheel Inc.; and Riverside Engine Inc.

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For more information about the NTPA, visit our website, www.NTPAPULL.com, follow us on social media at our Facebook page (ntpapulling)Twitter (@NTPApull)YouTube (NTPApull), Instagram (ntpa), and TikTok (@nationaltractorpulling) or call the NTPA office at 614.436.1761.

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