Chevy V8 Chrome Zinc 15° O-Ring Style Water Neck with 1/2" NPT Port

• 15° outlet angle routes the upper radiator hose cleanly in tight engine bays

• 1/2" NPT open port for a temp sensor or gauge fitting — plug or sensor sourced separately

• Fits Chevy Gen I small block (262-400 CID) and big block (396-454 CID) engines

• Zinc construction with chrome finish handles coolant heat and pressure

This 15° water neck creates the coolant outlet connection between the thermostat housing and upper radiator hose, with a chrome finish over zinc construction built to handle coolant system heat and pressure. The 15° outlet angle helps route the upper radiator hose cleanly where a straight neck wouldn't clear engine bay components. A 1/2" NPT port is machined into the neck and ships open — install a temperature sending unit, sensor, or gauge fitting, or add a separately sourced NPT plug if the port won't be used.

This water neck is built for Chevy Gen I small block (262-400 CID) and Gen II/V/VI big block (396-454 CID) engines only — it is not designed for LS-based (Gen III/IV) small block engines, which use a different thermostat housing design. An O-ring seal and mounting hardware are included; this outlet does not swivel after installation.

Not all Chevy small block or big block engines share identical thermostat housing bolt patterns across every model year — confirm your engine's housing bolt pattern before ordering, and verify the correct outlet angle for your radiator hose routing.

Engine Applications
Fits Chevrolet Gen I small block V8s from 262 through 400 CID and Gen II (Mark IV), Gen V, and Gen VI big block V8s from 396 through 454 CID. Suited to classic and performance builds, street rods, and restorations using a matching thermostat housing bolt pattern — LS-generation (Gen III/IV) small blocks use a different housing design and aren't covered by this fitment.

Installation
Confirm your thermostat housing bolt pattern before installing, since housing dimensions vary by engine year even within the same family. The included O-ring seals against the housing face; because this outlet is fixed rather than swiveling, hose alignment is set by the neck's 15° angle rather than by rotating it after mounting.

Does this fit LS engines?
No. This water neck is built for Chevy Gen I small block and Gen II/V/VI big block thermostat housings — LS-based (Gen III/IV) small block engines use a different housing design and require a different water neck.

What is the 1/2" NPT port for?
It's an open 1/2" NPT port sized for a temperature sending unit, sensor, or gauge fitting. No plug or sensor is included — you'll need to source the correct fitting for your setup, or install a standard 1/2" NPT plug if you don't plan to use the port.

Does this water neck include a plug for the NPT port if I'm not using it?
No. The port ships open with nothing installed. If you're not adding a sensor or sending unit, you'll need a separately sourced 1/2" NPT plug to prevent a coolant leak once the system is filled.

Why choose a 15° angle instead of straight or a different angle?
The 15° angle is a minor offset from straight, useful when a straight neck would position the upper radiator hose too close to another engine bay component. TSP also offers straight, 45°, and 90° versions for different routing needs.

Does this water neck swivel like the straight version?
No. This 15° neck has a fixed outlet angle and does not swivel — hose alignment is determined by the neck's angle at installation rather than by rotating it afterward.

Will this fit any small block Chevy, or only certain years?
It fits Gen I small block engines from 262 through 400 CID, but thermostat housing bolt patterns can vary by year even within that range — confirm your housing's bolt pattern before ordering.

Does this include a gasket or O-ring?
Yes. An O-ring seal is included for sealing at the thermostat housing face.

Is this a good fit for a restoration build?
Yes. The chrome-over-zinc finish and application-matched fitment suit restoration and classic builds looking for a clean appearance at the thermostat housing.