The Coan Racing COA‑12087 Rear Block-Off Plate is a precision-engineered steel plug designed to facilitate governor delete operations on GM Powerglide transmissions. Cadmium-plated for corrosion resistance and durability, this OEM-like plate securely seals the governor port on the transmission’s rear case, effectively blocking hydraulic flow and preventing leaks after the governor is removed.

Perfectly suited for drag-race or racing applications where the governor is no longer needed, the COA‑12087 installs as a bolt-in solution, restoring structural integrity and fluid sealing without requiring machining or welding. Whether you're customizing a trans-brake manual valve body or building a dedicated race Powerglide, this rear block-off plate delivers reliable performance and peace of mind under high-stress conditions.