COMP Cams Valve Spring 0.970in Inner - 973-1

The COMP Cams Valve Spring 0.970in Inner (Part #973-1) is a precision-engineered single inner valve spring designed to let engine builders construct a fully custom spring assembly tailored to their specific application. Whether you're building a street performance engine, a dedicated track motor, or a high-revving custom combination, COMP Cams inner springs like the 973-1 are a foundational component in a well-matched valvetrain stack. Sold individually, this spring gives builders the flexibility to spec their own dual- or triple-spring assemblies rather than accepting a one-size-fits-all kit.

Key Features & Benefits

• Custom Spring Assembly Flexibility: Sold as a single inner spring, the 973-1 allows engine builders to mix and match components and build the exact spring package their camshaft profile and application demands — rather than being locked into a pre-bundled kit.
• 0.970-Inch Outer Diameter: The 0.970 in. outer diameter of this inner spring is a precise sizing that fits within corresponding outer springs in a dual or nested spring configuration, ensuring concentricity and proper load distribution across the valvetrain.
• Known Coil Bind Height: With a coil bind height of 1.095 in., builders can accurately calculate installed height clearances and avoid coil bind at maximum valve lift — a critical step in safe, reliable engine assembly.
• Defined Spring Rate: The 134 lbs./in. spring rate provides a quantifiable starting point for valvetrain math, allowing builders to combine this inner spring with an appropriately rated outer spring to achieve a target seat and open pressure for their camshaft.
• No Damper Spring Included: This is a standalone inner coil spring without an integrated damper — ideal for builders who are sourcing components separately and want precise control over every element of their valvetrain assembly.
• COMP Cams Engineering: COMP Cams is a recognized name in performance valvetrain components, and their valve spring manufacturing process is designed to deliver consistent wire diameter, pitch, and load across production runs — important when running matched sets across multiple cylinders.
• Proposition 65 Compliance Noted: This product carries a California Proposition 65 designation, relevant to buyers in California who need to be aware of product chemical disclosures.

Specifications

• Part Number: 973-1
• SKU: CCA973-1
• UPC: 036584271031
• Spring Type: Inner valve spring (single)
• Outer Diameter: 0.970 in.
• Coil Bind Height: 1.095 in.
• Spring Rate: 134 lbs./in.
• Damper Spring Included: No
• Quantity: 1 (single spring)
• California Proposition 65: Yes

Fitment

The COMP Cams 973-1 is an application-specific inner valve spring intended for use in custom engine builds where the builder is constructing a multi-spring valvetrain assembly. It is not a direct OEM replacement spring for a specific make/model/year, and no specific vehicle fitment is listed by the manufacturer for this part number. Compatibility depends entirely on your cylinder head's spring pocket dimensions, retainer clearance, installed height, and the outer spring it will be paired with. Before ordering, verify your spring pocket inner diameter, installed height, and target seat/open pressure to confirm this spring's 0.970 in. OD and 134 lbs./in. rate fit your combination. If you're unsure whether this inner spring works with your heads and cam, contact our team for fitment guidance.

What's in the Box

• 1x COMP Cams Inner Valve Spring, 0.970 in. OD (Part #973-1)

Note: This listing is for a single spring. If you are building a full engine, order the quantity needed to match your cylinder count and valvetrain configuration.

Why Buy from ThreePiece.us

• Free Shipping: Every order ships free — no minimums, no surprises at checkout.
• Affirm Financing: Spread the cost of your build over time with Affirm financing, available at checkout.
• Expert Fitment Support: Our team has served 10,000+ customers and is available to help you verify parts compatibility and get the right components for your build. Reach us at [email protected] or call 813-535-5801.
• In Stock: The COMP Cams 973-1 is a regularly stocked product — no extended wait times associated with special-order items.
• 10+ Years of Experience: ThreePiece.us has been serving performance enthusiasts since 2014 with genuine products and knowledgeable support.

Frequently Asked Questions

Q: Is this listing for one spring or a full set?
A: The COMP Cams 973-1 is sold as a single (1) inner valve spring. If you need springs for a full engine build, make sure to adjust your quantity at checkout to match your cylinder and valve count.

Q: What is the coil bind height of the 973-1, and why does it matter?
A: The coil bind height is 1.095 in. This is the compressed height at which the spring coils make full contact and can no longer compress — a critical measurement when checking that your valve lift does not bring the spring to coil bind at full lift. Always ensure you have adequate clearance between your installed height at max lift and this coil bind figure.

Q: Does this spring come with a damper?
A: No. The 973-1 does not include a damper spring. It is a standalone inner coil spring intended to be used as part of a custom multi-spring assembly where the builder selects each component individually.

Q: I'm not sure if this spring fits my cylinder head — can you help?
A: Absolutely. Our fitment support team is available to help you cross-reference spring pocket dimensions, installed height, and rate requirements. Contact us at [email protected] or call 813-535-5801 before ordering if you have questions about compatibility with your specific heads or camshaft.