White Box Transmission Crossmember Hoop

Gen III Hemi Swap Transmission Crossmember Hoop for 1966-1970 B-Body Mopar - Use with NAG1 or 8HP70 Transmission & Crossmember WB130021

Part # WB130025
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Vehicle emissions regulations are not applicable to this item.

See Emissions Details
This transmission crossmember hoop is part of the most comprehensive line of Gen III Hemi swap components available for the Mopar B-Body. The Crossmember Hoop allows the installation of the popular, NAG1 5-speed or 8HP70 8-speed automatic transmission when used with the corresponding adapter plate (sold separately). The Crossmember Hoop replaces the very narrow factory Hoop on the original B-Body upper transmission crossmember allowing adequate clearance for drive shaft coupler and Speed sensor tone rings. This transmission Crossmember Hoop is specifically designed to replace the factory hoop and when used in combination with the WB130021 transmission crossmember will provide a bolt-in clearance solution with OE (Original Equipment) style strength and durability with no need for any fabrication or welding.


  • Engineered Transmission Mount System Works together with White Box Engine Mounting Brackets, Transmission Crossmember, Hooker Blackheart Long Tube Headers, and Exhaust Systems for an Easy Trouble Free Gen III Hemi Engine Swap in the 1966-1970 Mopar B-Body
  • Provides the Necessary Clearance Through the Upper Transmission Crossmember for the Drive Shaft Coupler and Speed Sensor Ring when Installing the NAG1 or 8HP70 Transmission
  • 1/2” Steel Upper Hoop Provides the Necessary Structural Integrity When Used in Combination with the WB130021 transmission Crossmember (no Welding Required)
  • No Cutting of the Transmission Tunnel Required
  • Accommodates Popular NAG1 or 8HP70 Transmission (Requires Transmission Specific Adaptor plate)
  • Uses the Factory Mounting Holes – For Easy Installation
  • Raw Unpainted Finish allows Easy Modifications & Great Value
  • Heavy Duty 3/16” and 1/2” Steel Construction for Strength and Durability
  • Includes Mounting Bolts & Instructions

About White Box

No frills, no fluff, no marketing; Just results! When you need to get the job done on a budget, look no farther than White Box. White Box offers budget-conscious solutions for engine swaps, exhaust systems, headers, fuel pumps, and even traction bars.

Application1966-1970 Mopar B-Body
Brand White Box
Emission Code6
Motor TypeChrysler Gen III Hemi
Product TypeTransmission Crossmember Support
Type of ComponentTransmission Crossmember
Part NumberWB130025

Vehicle emissions regulations are not applicable to this item.
• Installation of the WB130025 Crossmember Hoop requires cutting out the OE upper transmission Tunnel hoop and hammer massaging the transmission tunnel to provide additional space for the WB130025 to install into the transmission tunnel ( see installation Instructions) • Requires the use of WB130021 Transmission Crossmember to maintain proper structural integrity of the vehicle.

*Free Shipping & Handling only offered to the contiguous US on orders over $100, excludes clearance parts and oversized packages.

Some parts are not legal for use in California or other states with similar regulations.