Threaded sleeve Plug SBF Cylinder Head

The Trick Flow Threaded Sleeve Plug SBF Cylinder Head (MPN: TFS-51400265) is a precision-engineered thermactor plug designed for Small Block Ford engine builds. This component features a 5/8-11 inch outside thread that mates securely with your cylinder head's air injection port, while the 7/16-14 inch internal thread accepts compatible thermactor components. Manufactured from steel in a natural finish, this plug delivers the durability and corrosion resistance required in engine bay environments where temperature and humidity present ongoing challenges.

The dual-threaded design allows for secure installation without requiring additional adapters or modifications to your cylinder head casting. The 5/8-11 inch outer thread is the standard automotive air injection port size for classic and modern Small Block Ford applications, ensuring compatibility with factory and aftermarket thermactor systems. Steel construction with natural finish provides reliable service life without the cost and complexity of coated alternatives, making this an economical choice for rebuilders and engine shop professionals.

Small Block Ford engine builders—whether restoring original 289, 302, or 351W platforms or constructing performance variants—rely on OEM-specification plugs like this to seal air injection passages and maintain proper exhaust gas flow management. This threaded sleeve plug is essential during cylinder head assembly, engine overhauls, and thermactor system upgrades where original ports must be retained but not actively used. The compact 3.5 x 0.95 x 4 inch profile ensures straightforward installation without interference with surrounding engine components or manifold assemblies.