TECH UPDATE: 2026 Bellhousing Specs
Important Safety Update: Bellhousing Requirements for the 2026 Pulling Season
As we prepare for the 2026 pulling season, we want to make all competitors aware of important updates to bellhousing requirements. These changes are being implemented to improve safety and ensure consistency with current certification standards.
2026 Season Requirements
- All bellhousings must have a valid, non-expired certification sticker in order to compete during the 2026 season.
- All SFI 6.2, 6.3 and 6.4 bellhousings must display a valid and current SFI certification decal affixed by the manufacturer that includes the expiration date before being allowed to compete at any OTTPA event.
- SFI 6.1 bellhousings are no longer allowed beginning with the 2026 season.
- Bellhousing must be properly attached according to specifications listed below.
Competitors are strongly encouraged to verify the certification status and mounting of their bellhousing well before the start of the season to avoid any last-minute issues at tech inspection.
Bellhousing Attachment
- Bellhousing must be mounted as SFI certified by manufacturer with grade 8 studs or bolts that can be identified as grade 8. Socket head bolts allowed only for clearance problems.
- Bellhousing attachment must be by minimum grade 8 – 3/8-inch 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-inch (.375-inch) in steel or 3/4-inch (.750-inch) 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-inch steel or 1/4-inch aluminum.
- Any SFI bellhousing manufactured with 4 (four) quadrant/anti-rotation bolt holes, either 1/2-inch or 3/4-inch diameter, located two above crankshaft centerline and two below crankshaft centerline, must install proper size minimum grade 5 bolt and must pass through both block plate or block adapter and bellhousing and be securely tightened using equal hardness nut and washer per bellhousing manufacturer SFI certification.
- Bellhousing must be mounted with grade 8 studs or bolts per manufacturer’s bolt pattern for motor and bellhousing. All bolts must be in place.
- 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 – 1/4-inch aluminum 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.
Looking Ahead to 2027
- Aluminum bellhousings will no longer be permitted starting with the 2027 season, regardless of certification status.
This advance notice is intended to give teams adequate time to plan and budget for any required equipment upgrades.
What You Should Do Now
- Check your current bellhousing for certification type and expiration date.
- Make plans to replace any SFI 6.1 or uncertified bellhousings before the 2026 season.
- Begin preparing for the transition away from aluminum bellhousings ahead of the 2027 season.
Safety remains a top priority, and these updates are a critical step in protecting competitors, officials, and fans. If you have questions regarding acceptable bellhousings or certification requirements, please contact the organization before the season begins.
We appreciate your cooperation and look forward to a safe and competitive 2026 season.