Small Block Chevy Severe Duty Intake Valves - Set of 8 by Manley Performance
Severe Duty® series valves are the hallmark of Manley's presence in the performance and racing industry. No other company offers exhaust material XH-428 or intake material NK-844. Furthermore, no other material provides as clear a performance advantage. The ultimate tensile strength of XH-428 at 1500°F is nearly double that of competitors' EV-8. At 1000°F, Manley NK-844 exhibits more than four times the ultimate tensile strength of the best competing intake materials.
In addition to the superior strength and fatigue properties of Manley NK-844, our proprietary intake material demonstrates an incredible ability to resist margin fractures. In highly sealed combustion chambers, the force of fuel detonation can actually deform the intake valve and push it into the port. The effect of this continuous deformation on competing materials is that margin fractures eventually propagate around the valve, soon resulting in a missing pie-shaped section. Manley NK-844 is the absolute best material to combat catastrophic margin fractures.
Further evidence of the superiority of Manley Severe Duty® valves is evident in our comprehensive fatigue testing. In normal operation without valve float, a valve is subjected to 20,000 to 25,000 psi of stress. However, when a valve bounces on the seat, the stress quickly rises to 40,000 to 60,000 psi. Manley exhaust valves (at 40,000 psi and 1400°F) operated for 100,000,000 (100 million) cycles, while competing products failed at 100,000 cycles. This provides a 1000-fold increase in fatigue life.
Features
- Head Diameter: 2.020"
- Stem Diameter: 0.3415"
- Installed Height: 0.200" Long
- O/A Length: 5.140"
- Tip Length: 0.290"
- Underhead Angle/Radius: 10° x 3/8°
- Margin: 0.065"
- Seat Width: 0.080"
- Top: 5° Dish
- NK-844 Stainless Material
- Chrome Stems and Hard Tips
- Swirl Polished and Fully Machined
Benefits
- Superior stainless steel for high-temperature gasoline engines
- 1,000 times better fatigue strength than competing products
Please note: The image provided is generic and may not be an exact representation of the product you will receive.
Applications
- 2004–2007 Cadillac CTS V
- 2007–2008 Cadillac Escalade Base
- 2007–2008 Cadillac Escalade ESV Base
- 2008 Cadillac Escalade ESV Platinum
- 2007–2008 Cadillac Escalade EXT Base
- 1998–2002 Chevrolet Camaro Z28
- 1997–2008 Chevrolet Corvette Base
- 2001–2004 Chevrolet Corvette Z06
- 2005–2006 Chevrolet SSR Base
- 2006–2008 Chevrolet Trailblazer SS
- 2007–2008 GMC Yukon Denali
- 2007–2008 GMC Yukon XL 1500 Denali
- 2008 Hummer H2 Base
- 1998–2002 Pontiac Firebird Formula
- 2004–2006 Pontiac GTO Base
What's in the box?
- 8 - Valves
Warranty
- Due to the nature of their use, Manley products are sold without warranty.
Before You Order
〇 Regarding Import Consumption Tax
At Shaftoya Shopping Site, we pay the import consumption tax incurred during customs clearance on your behalf, so there will be no additional charges beyond the total amount paid at checkout.
〇Checking Compatibility
Our entire product database is based on North American vehicles (USDM). Please confirm whether the product is compatible with your Japanese-market vehicle (JDM) before ordering. (If you are unsure if the listed product is compatible with your vehicle, please feel free to contact us. Our support team will be happy to look it up for you.)
If you order without confirming compatibility, we cannot accept returns due to incompatibility.
Please note that even if items are sorted by selecting the year, manufacturer, and vehicle model in the tabs on our homepage, it does not necessarily guarantee that they will fit a Japanese-market vehicle without modification.
All products have been translated into Japanese using translation software. As there may be confusing expressions, please contact us before ordering if you have any questions.
○ Regarding Shipping
Shipping costs are paid at the time of settlement. An estimate for shipping costs will be automatically calculated when you enter your shipping address on the checkout page. For large items such as body parts, there may occasionally be a significant discrepancy between the automatically calculated shipping cost and the actual cost. In such cases, we will contact you individually via email.
Basically, all products are shipped internationally from our U.S. warehouse. Unlike domestic shipping in Japan, international shipping takes about 7 to 14 days, so please allow yourself plenty of time when ordering. If you are in a hurry, please contact us in advance to check delivery times. Note that all products are transported by air; they are not shipped by sea.
○ Regarding Compliance with Japanese Vehicle Inspection (Shaken)
Please be aware that all products we handle are designed and manufactured outside of Japan. They are not compliant with the "Japanese Vehicle Inspection System," and we cannot provide strength evaluation documents or similar paperwork for the Japanese inspection system. Therefore, all parts are sold for the purpose of "use on circuits, private property, or off-road," and you must accept full responsibility for the installation and use of these parts.
○ Regarding Warranty
Please inspect your items immediately upon arrival. Since all products are shipped internationally from outside of Japan, there is a possibility of shipping damage to the packaging or the product itself. We will only provide returns, refunds, or replacement exchanges for items that arrive damaged, are defective, or are not what you ordered, provided that you notify us within 7 days of receipt. Please note that for products sold through us, warranty-related support will be handled "exclusively through us." We do not coordinate with other companies or agencies located within Japan.