ICT Billet Turbo 400 (TH400) Speedometer Plug — Bare Billet Aluminium, Includes O‑Rings & Bolt

ICT Billet's billet aluminum speedometer plug for the Turbo 400 (TH400) is a precision-made blanking plug that replaces the stock speed sensor on Chevy V8 transmissions when a mechanical or GPS speed reading is not required.

Engineered and manufactured in Wichita, Kansas from aerospace-grade USA billet aluminum, this plug is a direct-fit solution for Turbo 400 transmissions commonly used behind small-block Chevy engines such as SBC 305, 327, 350 and big-block 383, including 5.0L and 5.7L V8 applications. It’s supplied as a bare aluminum assembly and includes the plug body, mounting bolt, and sealed O-rings so you get a complete, leak-resistant install right out of the box.

How does this plug work with transmissions that don’t need a speed sensor?

This plug occupies the sensor port on TH400 transmissions, providing a secure seal where a speedometer pickup would normally mount. It prevents fluid leaks and keeps contaminants out of the transmission case while eliminating an unused sensor location.

• Direct-fit for TH400 transmission speedometer port
• Includes bolt and O-rings for a reliable seal
• Replaces sensors when using GPS or electronic speed sources
• Prevents hydraulic fluid seepage and debris entry

Will this fit my Chevy small-block or big-block application?

The plug is designed specifically for Turbo 400 transmissions and is compatible with common Chevy V8 pairings, including SBC 305, 327, 350 and 383 engines, and 5.0L / 5.7L configurations. Verify your transmission model is TH400 to ensure compatibility.

• Fits TH400 (Turbo 400) transmission speedometer port
• Works with small-block and many big-block Chevy setups
• Ideal when the vehicle uses GPS or dash electronics for speed
• Sold as a bare aluminum plug suitable for most retrofit projects

What materials and manufacturing standards were used?

Made from aerospace-grade, USA-produced billet aluminum, this plug is CNC-machined in Wichita to tight tolerances for longevity and corrosion resistance. The billet construction provides a sturdy, lightweight part that resists deformation compared with cast or stamped alternatives.

• Aerospace-grade billet aluminum sourced in the United States
• CNC-machined for precise thread and seat engagement
• Supplied with O-rings to protect against leaks and contamination
• Proudly manufactured in Wichita, Kansas by ICT Billet

How do I install the speedometer plug and what hardware comes with it?

Installation is straightforward: remove the original speedometer sensor or cap, clean the mounting surface, fit the O-rings, and torque the plug’s mounting bolt to the manufacturer’s recommended spec. The kit ships with the plug, the correct bolt, and O-rings to make installation simple and leak-proof.

• Includes plug body, mounting bolt, and O-rings
• Simple thread-in installation—no special tools beyond common hand tools
• Torque to transmission manufacturer’s specifications
• Can be used as a permanent blank or temporary cap during conversions

Who is this for? This ICT Billet speedometer plug is intended for builders, restorers, and customizers who use Turbo 400 transmissions in Chevy V8 projects and do not require a mechanical speed sensor — for example, vehicles converted to GPS speedometers, transmissions used in race/track cars, or restorations where the original electronic sender is not desired. It’s a practical choice for anyone seeking a durable, precision-made blanking plug manufactured in the USA and supplied with the necessary hardware for immediate installation.