1.75 Alum.Cap & Steel Bung Assembly

The 1.75 Alum.Cap & Steel Bung Assembly (PN6551) is a critical component designed for fuel system management and tank venting in automotive applications. Whether you're building a custom fuel system, performing a fuel tank swap, or upgrading your vehicle's fuel delivery setup, this assembly serves as a sealed interface between your fuel tank and vent system. Mechanics and fabricators rely on this type of assembly to ensure proper pressure regulation and prevent fuel vapor escape during operation and storage, making it essential for both street and competition vehicles.

Engineered with a 1.75-inch aluminum cap paired with a steel bung, this assembly combines lightweight construction with durability where it counts. The aluminum cap minimizes weight while providing excellent corrosion resistance, while the steel bung delivers the structural integrity needed to withstand tank pressurization and environmental exposure. The 4.2-inch overall length accommodates most standard fuel tank configurations, and the compact 2.1 x 1.95-inch cross-section makes installation straightforward even in tight engine bays. At just 0.24 lbs, the assembly adds virtually no mass to your fuel system while maintaining reliable sealing performance across temperature cycling and vibration.

This bung assembly is ideal for fuel system customization, tank fabrication projects, and fuel cell installations where OEM filler caps are replaced or unavailable. It works seamlessly with fuel line routing, vent lines, and rollover valves found in modified street cars, off-road vehicles, and track cars. Installation requires basic hand tools and is compatible with most universal fuel tank configurations—simply thread the bung into your tank opening and secure the cap to complete the seal. Whether you're a professional fabricator managing high-flow fuel systems or an enthusiast tackling an engine swap, this assembly delivers the reliability and ease of installation that serious builders demand.