12an to 3/4npt Male to 6an 3/8npt Female

The 12AN to 3/4NPT Male to 6AN 3/8NPT Female fitting from REDHORSE PERFORMANCE is a critical adapter for custom fuel system and hydraulic line configurations where mixed fitting standards must be reconciled. As an experienced mechanic, you know that engine bay layouts demand flexibility—fuel rails, boost controllers, and nitrous systems often require adapters that bridge industry-standard NPT pipe threads with AN (Army-Navy) automotive fittings. This compact adapter eliminates the need for multiple components, reducing leak points and simplifying installation on high-performance fuel injection, forced induction, and precision fuel delivery systems.

REDHORSE PERFORMANCE adapters are engineered with precision-machined aluminum construction and hard-anodized finish, ensuring corrosion resistance in fuel and boost environments while maintaining reliable thread sealing. The dual-port design—accepting a 12AN inlet on one end and offering a 3/4NPT male connection while simultaneously supporting a 6AN outlet and 3/8NPT female port—provides exceptional versatility for custom fuel distribution blocks, regulator plumbing, and intercooler charge piping. Proper thread sealant (PTFE tape or Teflon-based pipe dope) on NPT ports ensures positive pressure integrity without compromising flow rates critical to fuel system efficiency.

This adapter serves engine builders, tuners, and DIY enthusiasts upgrading fuel systems on turbocharged, supercharged, or carbureted platforms where OEM fittings don't align with custom manifold or rail designs. Weighing just 0.095 lbs and measuring 2.85 x 1.4 x 3.75 inches, it fits tight engine compartments without adding bulk. Installation is straightforward—hand-tighten NPT ports to prevent thread galling, then torque down with a wrench to manufacturer specifications. Compatible with fuel, coolant, boost pressure, and vacuum applications where NPT and AN standards meet, making it essential for any serious performance fuel system rebuild.