Tech Information

The following rule goes into effect Aug 10, 2022:

New rule added to the 2022 NTPA rulebook (general rules) pg 27 letter G under engines, a new #7 which reads:

Diesel fuel injection lines must be a minimum of 24 inches in length from the injection pump to the injector. This applies to all classes with a diesel engine.

Note: The Heavy Pro Stock class, V-8 engines and high pressure common rail systems including electronic fuel injection are exempt of this rule.

Items/rule changes that go into effect for the 2022 season

NTPA Rule Update: Effective immediately:

Page 28 of the 2022 NTPA rulebook “Shielding” #1 letter now reads:

J. All inline turbocharged engines are required to have a cable(s) placed between first and second cylinder through exhaust manifold port area. Cable must be a minimum of one (1) 3/8 manufactured pendant line with a rating of at least 3000 lb or more with a tag from the manufacture that indicates rated load capacity with swaged sockets.


Two (2) 3/8″ cables with a minimum of 4 clamps at the splice or crimps with a coupler on each cable. Cable(s) must circle the entire head/block assembly with a maximum of 4″ slack.

Example of the pendant line and tag:


Modifieds, Minis, and Trucks must use SFI approved bellhousing.

  • Bellhousings must be mounted as SFI certified by manufacturer with grade 8 studs or bolts that can be identified as grade 8. No hex socket head bolts.
  • Bellhousing attachment must be by minimum grade 8 – 3/8” diameter bolts or studs and must pass through bellhousing flange and block plate. Fasteners installed into engine block or block adapter must be at a depth of 3/8” (.375”) in steel or ¾”(.750”) in aluminum. All other bolts must sandwich bellhousing and block plate using a grade 8 nut and washer. All block plates and block adapters must be made from billet steel or aluminum.
  • All automotive type engines with SFI bellhousings and clutch must run a full block plate, either a unit commercially available, or fabricated from a minimum 3/16” steel or ¼” aluminum.
  • Any SFI bellhousing manufactured with 4 quadrant bolt holes, either 1/2” or ¾”, located two above crankshaft centerline and two below crankshaft centerline, must install proper size minimum grade 5 bolt through both block plate or block adapter and bellhousing per bellhousing manufacturer SFI certification.
  • SFI 6.2 bellhousing must be mounted with qty. 18 – 3/8” grade 8 bolts or studs identifiable as grade 8. No hex socket head bolts allowed.
  • SFI 6.1 and 6.3 bellhousings must be mounted with qty. 15 – 3/8” grade 8 bolts or studs identifiable as grade 8. Qty of 7 installed above crankshaft centerline and qty. 8 installed below crankshaft centerline. No hex socket head bolts allowed.
  • All bellhousing liner(s) must be made from steel or titanium. Liner must be flush with bellhousing flange / mounting surface and fastened with qty. 1 – ¼” bolt threaded into liner. No modification or rearward movement of liner away from flywheel to allow for larger flywheel or ring gear. Liner can be notched for starter pocket in SFI 6.1 or 6.3 bellhousings.
  • Starting Jan 1, 2023 all SFI bellhousings regardless of material i.e. steel, titanium or aluminum must display a current SFI sticker with a expiration date affixed by the manufacture. The NTPA steel stamp will no longer be acceptable as a replacement for SFI decal after Jan 1, 2023.

Mini Rod, Transmission Mounting (with planetary type rear axle only)

  • Grade 8 studs, hardened washers, and nuts required when installed externally into bellhousing. Grade 8 bolts with hardened washer acceptable in applications where fasteners are installed from inside bellhousing and threaded into transmission case.
  • Transmission must be fastened to SFI bellhousing using a minimum 2” total bolt diameter.
  • Total bolt circle calculations by qty. x stud diameter
    • 8 – 3/8” (.375”) = 3”
    • 6 – 3/8” (.375) = 2.250”
    • 5 – 7/16” (.4375) = 2.1875”
    • 4 – ½” (.500) = 2”
  • Total bolt circle requirement by transmission manufacturer
    • SCS and TRB – qty. 8 – 3/8” grade 8 studs
    • Profab – qty. 4 – ½” grade 8 studs
    • B&J / Lenco – qty. 5 – 7/16” grade 8 studs


  • All helmets must be Snell 2015 or newer

Pull Off

  • Eliminate rules 8 and 9 on pg. 88 related to pulloff per proposed agenda item

Diesel Fuel

  • Dielectric constant reading increased to 150 / 13.4 based on meter used.

Limited Pro Stock

  • Steel billet cylinder head(s) allowed.

Classic Super Stock

  • Classic Super Stock class now a recognized Regional National class.

Limited Light Super Stock

  • Engine
    1. Maximum of 410 cubic inches for single turbo charged diesel engines, intercoolers allowed. This engine combination can run a maximum of (1) 3×4 turbo with MAF enhancements, 0.200 MAF enhancements. No forward facing MAF OR (1) 3.4×4 smooth bore turbo.
    2. Maximum of 470 cubic inches for single turbo charged diesel engines. No intercoolers allowed. (The 478 Hercules engine will be legal to run in its factory combination 0% variance on CID). This engine combination can run a maximum of one (1) 3.4 x 4 smooth bore turbo OR (1) 3×4 turbo with MAF enhancement of 0.200 MAF enhancement. No forward facing MAF.
  • Front Axle Suspension – approved for this class.

Pro Farm

  • Turbocharger – require 3” smooth bore (intake and exhaust) turbo.
  • Rule 5 – 3” intake and exhaust slug option eliminated.
  • Weight changed to 9500 lbs.

Mini Rod

  • Stabilizer Bars: Center of stabilizer bar pad must extend 2” behind tire.

Light Unlimited

  • Two-engine limit removed from class rules.


  • Driveline shields must be made of steel, minimum 5/16” thick, and extend at least 6 inches past centerline of each universal joint. No more than ¼” gap between end of shield and gear box or differential. All front driveshafts to have a 5/16” x 2” wide steel, 360 degree safety loop installed at center of front driveshaft and securely mounted to each frame rail by qty. 2 – 3/8” grade 5 bolts evenly spaced.
  • Engines are required to shield all rotating mass mounted to front of crankshaft 360 degrees from front of engine block to one inch in front of the rotating mass. Shield made from 1/8” steel must be constructed to cover outer circumference of damper and extend no more than 1 inch beyond front of damper. Damper shield must be formed to within 1 inch of circumference. Shield must extend rearward to front engine mount, engine block, or oil pan and have minimum 2” lip bent upward in front of damper. Shield must be independently fastened to engine and or chassis with minimum qty. 4 – 3/8” grade 5 bolts.

Shielding on all V or Y-type engines

  • Side shield must extend from base of head or the uppermost part of the piston and travel to 2” below bottom center of crankshaft throw, and be securely fastened.
  • a. Side shield must be made from minimum .060” steel or aluminum and positioned within 3 inches of block.
    b. Shield must cover full length of block and extend from bottom of cylinder head to 2 inches below bottom center throw of crankshaft.
    c. Shield must be bent 90 degrees at bottom and extend horizontally inward to meet engine oil pan

Rules and Regulations:

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 $6.00 plus $2.00 shipping and handling to WPI/NTPA, 6155-B Huntley Rd. Columbus, OH 43229.

Head Tech Official
Roger Kutz
(262) 473-2531