O-Ring Carb Nut Short 5/16-18

The O-Ring Carb Nut Short 5/16-18 from Allstar Performance is an essential fuel system fastener designed for carburetor inlet fittings and fuel line connections on race cars, hot rods, and street machines. This short-format nut accommodates tight engine bay layouts where standard-length hardware creates clearance conflicts. Whether you're building a small-block V8 with a street carburetor or assembling a full race fuel system, having the correct nut size and O-ring seal prevents fuel leaks and maintains system integrity under pressure and vibration.

Engineered with a 5/16-18 thread pitch, this nut threads onto standard fuel line adapters and carburetor fuel bowl inlets without modification. The integrated O-ring seal compresses between the nut face and fitting shoulder, creating a fuel-tight seal that eliminates the need for thread sealant or PTFE tape—critical in high-vibration engine compartments where tape can migrate or degrade. The compact short design reduces thread engagement length while maintaining full clamping pressure, making it ideal for carburetors with closely spaced fuel ports or when installing braided stainless fuel lines near intake manifolds or cylinder heads.

Carburetor builders, engine builders, and hot rod enthusiasts rely on Allstar Performance hardware for consistent fitment and reliability across multiple fuel system configurations. This nut pairs with Allstar or equivalent fuel line adapters (dash sizes 6, 8, or 10) and works with single or dual carburetor setups. Its steel construction ensures durability and performance under demanding conditions.