Description

When installing a high-performance mechanical water or oil temperature gauge (like the Longacre AccuTech series) into a race engine, builders often run into a plumbing mismatch. The gauge’s thick capillary tube and sealing nut rarely fit directly into factory coolant or oil ports. If the intake manifold or cylinder head features a slightly smaller 3/8″ port, the Longacre 3/8″ NPT Water Temp Manifold Fitting is the exact adapter required to complete the installation.

Machined from solid brass, this straight adapter threads directly into standard 3/8″ NPT engine ports. The female end features a precision-machined 5/8″-18 thread, providing a secure, leak-free seat for the mechanical gauge’s bulky temperature sending probe. It perfectly seals the capillary tube while ensuring the probe bulb sits directly in the fluid flow, guaranteeing dead-accurate temperature readings under extreme racing pressures.

Key Features

Mechanical Gauge Adapter: Specifically engineered to step down the bulky 5/8″-18 sealing nut found on most mechanical water and oil temperature gauges to fit smaller engine block ports.
3/8″ NPT Male Base: Features a standard 3/8-inch National Pipe Thread (NPT) male end, allowing for a direct installation into standard small-block Chevy/Ford cylinder heads, intake manifolds, or aftermarket water necks.
Solid Brass Construction: Machined from premium natural brass. It will not rust or corrode from exposure to water-based racing coolants and provides an excellent, gall-free seal to prevent high-pressure fluid leaks.
Universal Compatibility: While perfect for Longacre AccuTech mechanical gauges, the standard 5/8″-18 female thread pitch makes it universally compatible with almost any major brand of mechanical temperature gauge on the market.