Granatelli Motor Sports 451000 Valve Cover Breather Insert Threaded Female Receptacle

The Granatelli Motor Sports 451000 is a threaded, female-receptacle valve cover breather insert designed to add or replace a breather port on virtually any valve cover — no welding required. This screw-in baffle kit makes it easy to install a 1-inch diameter press-in breather system into your valve covers, whether yours lacks a breather hole entirely or you need an additional port in a different location.

The insert features a 1 in. double O-ring I.D. female receptacle compatible with most standard push-in breathers (sold separately). An internal baffle prevents oil from being pushed out through the breather under crankcase pressure, keeping your engine bay clean and your breather functional. Installation requires drilling a 1.375-inch hole into the valve cover.

Key Features:

• Threaded, screw-in design — no welding required
• 1 in. double O-ring female receptacle fits most standard push-in breathers
• Internal oil baffle prevents unwanted oil blowout
• Requires a 1.375 in. hole drilled into the valve cover
• Universal design suitable for valve covers without existing breather holes or where an additional port is needed
• Kit includes lock nut, sealing washer, O-ring, and threaded baffle
• Not CARB legal — not for sale in California

The Granatelli Motor Sports 451000 is a practical, no-weld solution for builders and enthusiasts looking to add proper crankcase ventilation to custom or performance valve covers.