How do I know if these valve locks are the correct size for my valves?

It is critically important that your valve locks match your valve size. If the two halves of the lock fit together without any gap, they are too large. If they fit too loosely and leave a gap between the middle of the lock and the outer diameter of the stem, they are too small.

What is the purpose of the tang on a valve lock?

The tang on a valve lock is primarily for temporarily locating the lock, retainer, and spring relative to the valve. The main holding force comes from the retainer's taper creating a collet effect that binds the lock and retainer together.

Are these valve locks suitable for high-performance engines with heavy valve springs?

These locks are recommended for street applications with lighter valve spring loads. The tang is not designed to withstand open spring loads of 1000 lbs or more.

COMP Cams Valve Locks 3/8in Single Groove 603-16

Name: COMP Cams Valve Locks 3/8in Single Groove
Brand: COMP Cams
Price: 25.24 USD
Availability: InStock

COMP Cams Valve Locks 3/8in Single Groove

$25.24

On Backorder

Order now to reserve yours — we'll ship as soon as stock arrives. Full refund if we're unable to fulfill.

COMP Cams Valve Locks 3/8in Single Groove. Hardened steel street locks for stock engine rebuilds.

Key Features

Fits 168+ vehicle make/model combinations.
Set includes 16 pairs of hardened steel street locks.
Features a 7-degree angle and is designed for a 3/8 inch valve stem size.
Single groove design.
Recommended for street applications with lighter valve spring loads.
Critical for proper valve train function and engine rebuilds.

⚠️ CA WARNING: This product can expose you to chemicals known to the State of California to cause cancer and/or birth defects or other reproductive harm. Learn more

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Will this fit your vehicle?

Product Details

COMP Cams is well-known for performance engine components, and these 3/8 inch single groove valve locks are a solid option for stock engine rebuilds. They are made from hardened steel and feature a 7-degree angle, designed to work with a 3/8 inch valve stem size. It's important that your valve locks match your valve size precisely. If the two halves of the lock fit together without any gap, they are too large. Conversely, if they fit too loosely and leave a gap between the middle of the lock and the outer diameter of the stem, they are too small.

While the tang on a valve lock helps temporarily position the retainer and spring, its primary role isn't to hold against high spring loads. The real holding power comes from the retainer's taper nesting around the lock, creating a collet effect that binds them together. This effect tightens as spring force increases, keeping everything securely in place. These locks are recommended for street applications with lighter valve spring loads.

This set includes 16 pairs of these hardened steel street locks, suitable for a wide range of American and some Chevrolet vehicles from the 1960s through the 1990s, such as the Chevrolet Chevelle, American Motors Gremlin, and Chevrolet C10 Pickup.