Chevy V8 Aluminum Straight Water Neck - Polished

• Straight aluminum outlet connects thermostat housing to upper radiator hose

• Swivel design and included O-ring simplify hose alignment and leak-free sealing

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

• Polished finish; also offered in black and 15°/45°/90° angles for other routing

This straight aluminum water neck creates the coolant outlet connection between the thermostat housing and upper radiator hose, with a polished finish that gives the engine bay a clean, finished look. The straight outlet routes the upper radiator hose directly, and an included O-ring seal helps reduce leak points at the housing connection.

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. The swivel design allows the outlet to rotate for hose routing flexibility, and mounting hardware is included.

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 and outlet angle match before ordering.

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. This straight-outlet design suits 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 and outlet angle before installing, since housing dimensions vary by engine year even within the same family. The included O-ring seals against the housing face, and the swivel outlet can be rotated after mounting to align the upper radiator hose without disturbing the seal.

Does this fit LS engines?
No — this water neck is designed 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 compatible LS-style water neck.

Will this fit any small block Chevy, or only certain years?
It's designed for Gen I Small Block Chevy engines from 262 through 400 CID. Because thermostat housing configurations can vary, verify your housing's bolt pattern and sealing surface before ordering.

Can I use this with an aftermarket thermostat housing?
Yes, provided the bolt pattern and O-ring sealing surface are compatible. Verify these dimensions against your aftermarket housing before installation.

Does the swivel design affect the seal?
No — the O-ring seals at the thermostat housing mounting face, while the swivel design allows the outlet to be positioned for better hose alignment.

What's the difference between the straight version and the angled versions?
The primary difference is the outlet angle. Straight, 15°, 45°, and 90° versions share the same basic fitment and sealing design, allowing you to choose based on radiator-hose routing and engine-bay clearance.

Do I need a heater bypass with this water neck?

This water neck does not include a heater bypass provision. If your cooling-system configuration requires a bypass, it must be accommodated elsewhere in the system.

Is this suitable for a restoration build looking for a factory-style appearance?

Yes — the polished aluminum construction and straight outlet provide a clean, traditional appearance that works well in classic and restoration-style engine bays.