Tech Information

Download the 2026 rules HERE

2026 NTPA Pulling Rules

Summary of new and revised rules and procedures approved by WPI and NTPA Executive Board of Directors for the 2026
season.

Light Pro Stock

  • Component chassis will be accepted beginning 2027 season
  • Boards to decide any weight compensation between OEM vs Component chassis
  • No weight variance between OEM and component chassis beginning 2030 season

GN 4.1 Pro Stock

  • PS 4.1 added to GN circuit beginning with the 2026 season
  • Component chassis will be accepted beginning 2028 season
  • Boards to decide any weight compensation between OEM vs Component chassis
  • No weight variance between OEM and component chassis beginning 2031 season
  • 4.1 Pro Stock at GN level are limited to competing in their own division.

Video Review – GN / SN Levels only – Effective 01-01-2026

  • If on track decision is contested, the NTPA appeal process must be followed
  • If appeal is accepted, NTPA Director of Technical Services has the right to consider using video
    for further evaluation (not mandatory)
  • Only “Official NTPA Video” (i.e. from Full Pull and/or AP Productions) will be utilized in this
    consideration
  • No personal, contestant, spectator, or non-official video allowed to be utilized regardless of
    situation
  • NTPA Track Officials and the NTPA Director of Technical Services can utilize WPI Exec. Board
    Members to assist in the decision making process
  • NTPA Director of Technical Services to notify WPI Executive Board of final decision
  • If NTPA Track Officials are unable to come to an agreement, the NTPA Director of Technical
    Services has the final decision
  • NTPA Director of Technical Services to make the announcement regarding the final decision
  • NTPA Director of Technical Services to notify the NTPA Executive Director of the final decision
  • NTPA Executive Director to assure any/all resources are made aware of any change or affect
    regarding final standings (i.e. NTPA Competition Department, NTPA Website, NTPA App
    Administrator, Full Pull Live, Full Pull Picks, etc.)
  • NTPA Executive Director to assure any/all event standings posted match the final decision

Semi Rear Axle Suspension

  • Positive rear drive axle suspension stops required
  • Axle suspension must be activated against stops before drawbar height is measured
  • Maximum drawbar height remains at 18 inches
  • Rear suspension stop mechanism must be solid and rigid, clearly visible, and painted orange
  • Only welded or bolted assembly accepted
  • No slide or slotted adjustment mechanism can be used
  • Suspension stops cannot in any way be adjustable from the cab

Electronic Water Injection

  • Datalogger or any onboard ECU can only turn water injection on or off
  • Any valve used for water injection must function as either open or closed
  • Use of PWM (pulse width modulation) or any control valve type that incorporates a variable
    control function for water injection is prohibited

Fuel Tech / Coil Over Ignitions

  • Fuel Tech or any multi-coil (coil on spark plug or near spark plug) systems is not accepted in any
    V-8 automotive application

Super Stock FWD

  • Rules for this division will be clarified by engine cubic inch displacement rather than by Region
  • Class rules will distinguish between 530 and 410 cubic inch trucks to clarify specific rules that are
    different based on engine displacement

Turbocharger Safety Blanket – all turbochargers

  • Safety blanket is required on all turbocharger compressor housings in all divisions at all levels
  • All turbocharger safety blankets must be constructed with a minimum of 5 layers of Kevlar or a
    SFI 4.1 rating

Turbocharger Air Outlet Pipe Blanket

  • LT PS and LLSS are added to the current turbocharger air outlet pipe blanket rules currently
    stated for PS 4.1

Turbocharger Intake Cross

  • All single turbocharger applications listed requires a one –piece 3/8” billet cross located within 8
    inches of compressor wheel inducer blades and behind the air shutoff gate – maximum cross
    diameter by division is as follows:

    NTPA Division Max. Cross Diameter                      Max. Cross Diameter
    o SF, PF, HF, LLSS, PS 3.0 / 3.6 4X4 7” max.                           7″ max.
    o PS 4.1 8” max.                                                                     8″ max.
    o LT PS 9” max.                                                                      9″ max.

Diesel Fuel Testing

  • NTPA will continue to measure dielectric constant of diesel fuel using proven, high quality test
    instruments.
  • The maximum DC reading using NTPA test instruments will remain at 13.4
  • When a competitor or supplier uses a Digatron FT64 or similar meter, using a maximum spec of
    135 will align with the 13.4 spec used by NTPA

Diesel Fuel Supplier – GN Level

  • NTPA plans to pursue a single diesel fuel supplier for the GN circuit for the 2026 season

Protests Fees

  • Protest fee increases from $500 to $2000 for all protests except fuel and water which will
    remain at $1,000 currently
  • Both protested and protester items or vehicles will be subject to the same inspection – all
    current protest procedures will be followed
  • NTPA retains $500 of the protest fee to offset costs related to inspection including equipment,
    travel, and etc. in cases such as measuring engine displacement

Modified FWD

  • Maximum overall length from center of rear axle to furthest point forward is 193 inches
  • Wheelbase is limited to 131” min. up to 133” max.
  • Minimum drawbar length from center of rear axle to point of hook is 39.5 inches
  • Drawbar length by percentage of wheelbase has been deleted

SSD 4X4 Trucks – Drawbar Length

  • Minimum drawbar length from center of rear axle to point of hook is 44 inches
  • Drawbar length by percentage of wheelbase has been deleted

SFI Specs

  • SFI required equipment to be compiled and listed in rule book by division in chart form
  • Chart for each division to be made available as a separate document for handout

Event Interruption / Cancellation – GN / SN Events

  • Director of Technical Services working in cooperation with promoter has the option to run
    Grand National vehicles only in a GN class that is interrupted or time is limited due to weather,
    curfew, lack of time, or whatever situation might require class size to be limited to allow
    completion of session for those being awarded GN points

7,500 lb. GN Modified

  1. Engine Combinations

b) Three blown automotive engines equipped with 18-71 superchargers at 70% maximum overdrive or PSI screw-type superchargers limited to C or D rotor only at 94% maximum overdrive

High Pressure Common Rail Fuel System – Safety Shutdown

  1. All pulling vehicles with engines equipped with High Pressure Common Rail Fuel Systems (HPCR) are required to incorporate a manual switch that can be operated by track officials that will disconnect battery supply to the engine ECU which controls fuel injection. The main battery disconnect can be used for this purpose if switch is labeled and located in the required position.
  2. Pro Street Diesel 2.6 4X4 Trucks, Pro Stock and Super Stock Diesel 4X4 Trucks
    1. HPCR disconnect switch must be located at left end of the front weight box or weight rack. Switch must be easily accessible and identifiable.
  3. Semi
    1. HPCR disconnect switch required to be located at left end of bumper. Switch must be easily accessible and identifiable.
  4. This rule does not eliminate the required 3-way fuel bypass valve located in fuel supply system before the high pressure pump. Refer to F. General Rules – section 19. Safety – sub-section k. Fuel Shut-off / Diesel Bypass Valve for more details.

Intercooler Containment

  1. All remote mounted intercoolers (ie. intercoolers not direct mounted to the engine within the engine shielding) must be securely fastened to the chassis or to a structure that is mounted directly to the chassis. Intercooler cannot be suspended by the air inlet or outlet pipes.
  2. Intercooler cannot be mounted behind the vehicle firewall within the driver’s compartment.
  3. Intercooler housings made from a billet material will be required beginning 2027 NTPA season in Heavy Pro Stock, Super Stock Diesel 4X4 Trucks, and Semi divisions. No welded housings will be accepted after end of 2026 season.
  4. All intercoolers not contained within the normal engine shielding must be shielded the same as a turbocharger not under the hood. Refer to F. General Rules – section 22. Shielding – sub-section g. Intercooler Shielding for more details.

TWD Tires (all levels) – effective 2027 season

  1. Maximum tire size limited to 143-inch circumference out of the mold and 19.5-inch tread width after cutting, mounted on rim, and in ready to compete condition.
  2. Tires in competition will be measured and monitored during 2026 season to support any change necessary to these specs.

Pro Street 2.6 4X4 Trucks

  • Use of non-OEM, aftermarket driveline components are accepted in Region 3 only

Pro Charger (centrifugal supercharger)

  • Pro Charger (belt driven, centrifugal supercharger) is not accepted in any division of NTPA competition

Modified Mini

  • Turbine engines are not accepted in the Modified Mini division at any level of NTPA competition

Limited Modified Rules – RN Level – Proposed for 2027 Season

  1. All Modified tractor overall general and safety rules apply.
  2. Maximum weight is 6500 lbs.
  3. One blown automotive engine with maximum 14-71 supercharger
    1. Maximum 2 valves per cylinder, one spark plug per cylinder, limited to 575 CID
  4. One Allison engine
    1. Maximum of 9.6 to 1 supercharger ratio with stock Allison 9.5-inch blower wheel.
    2. Must use SFI spec 4.2 blower containment device.
  5. One Packard V12
    1. Maximum 6.5 to 1 supercharger ratio
    2. Stock Packard butterfly must be utilized.
  6. Any combination of N/A automotive style engines with a combined displacement of 1,400 CID
  7. Any combination of forced induction, wedge head, automotive style engine with combined displacement of 750 CI, no billet blocks or heads allowed.
    1. Turbochargers limited to one per bank, non-staged.  76mm inducer compressor side, 76mm exducer turbine side.
    2. Engine driven blowers allowed are centrifugal and roots. Maximum limit of (2) 8-71 roots blowers.
    3. No screw type blowers
    4. No intercoolers
  8. One Ag or Industrial style engine limited to 505 CID displacement on alcohol
    1. Aftermarket aluminum heads allowed no overhead cams allowed
    2. Turbo is limited to 4.1” smooth bore inlet opening with maximum 4.5-inch exhaust wheel, intake and exhaust wheel must protrude 1/8-inch into housing
    3. No MAP width ring enhancement
  9. Single Diesel Engine – maximum 540 CID
    1. Turbocharger limited to 4.8-inch intake opening – MAP width ring opening accepted
    2. Intake and exhaust wheel must protrude 1/8-inch into housing
    3. No intercoolers
    4. All LT Pro engine rules apply
  10. Single Diesel Engine – maximum 640 CID
    1. Turbocharger limited to 4.1-inch smooth bore intake opening
    2. Intake and exhaust wheel must protrude 1/8-inch into housing
    3. No intercoolers
    4. All other 4.1 PS engine rules apply
  11. Any combination of automotive style diesel engines, I.e. Duramax, Cummins, and Powerstroke
    1. Engine(s) limited to combined 900 CID maximum displacement.
    2. Limited to one turbocharger per engine with maximum 76 mm inducer compressor side and 88 mm exducer turbine side
    3. Intake and exhaust wheel must protrude 1/8-inch into housing
    4. No intercoolers
  12. Turbine horsepower maximum military rating of 2,300 hp. single or any combination accepted. All turbines must be inspected annually by NTPA Technical Services and operated within military specifications. Average additional horsepower is 10% for water and 10% for methanol
    1. One Lycoming T53 L-13 turbine rated at 1400hp military spec – water and alcohol injection accepted
    2. Twin Lycoming T53 L-1, L-11 – water and alcohol injection accepted
    3. One Lycoming T55-L5 turbine rated at 2200hp military spec. Must be sealed at authorized repair shop. No alcohol or water injection accepted
  13. One 1,100 CID Ford GAA Engine on alcohol
    1. Limited to two, non-staged turbochargers, one per bank
    2. Maximum 88mm inducer on compressor side and 99mm exducer on turbine side
    3. Intake and exhaust wheels must protrude 1/8-inch into housing.

Are you a puller? Or just thinking about becoming one? Or maybe you’re a fan and want to know the nuts and bolts of this pulling thing. Whatever your need, the latest Official NTPA Rulebook has all the answers about what’s legal and what’s not. It also explains event operations and the NTPA points system.

Click here to order your copy of the NTPA Rulebook from our online store!

You can also call the NTPA office at 614-436-1761 or mail $8.00 to WPI/NTPA, 1299 Campbell Road
Marion, OH 43302. (Shipping and handling are included)

Head Tech Official
Roger Kutz
(262) 473-2531
rckutz@gmail.com