Small Block Chevy Severe Duty Exhaust Valves - Manley Performance Set of 8
Severe Duty® series valves are Manley's premier product in the performance and racing industry. No other company in the world offers the exhaust material XH-428 or intake material NK-844. Furthermore, no other material demonstrates such a clear superiority over others. 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 intake materials from competitors.
In addition to the exceptional strength and fatigue properties of Manley NK-844, our proprietary intake material demonstrates an incredible ability to resist string-type fractures. In highly sealed combustion chambers, fuel explosions can actually cause intake valves to deform and be pushed into the port. The effect of this continuous deformation on competitor materials is that string-like fractures eventually spread around the valve, soon resulting in a missing pie-shaped piece. Manley NK-844 is the absolute best material for combating catastrophic string fractures.
Further evidence of the superiority of Manley Severe Duty® valves is evident in our comprehensive fatigue testing. During normal operation without valve float, valves are subjected to 20,000 to 25,000 pounds of stress. However, when the valve bounces on the seat, the stress immediately rises to 40,000 to 60,000 pounds. Manley's exhaust valves (at 40,000 psi and 1400°F) operated for 100,000,000 (100 million) cycles, while competitor products failed at 100,000 cycles. This represents a 1000-fold improvement in fatigue life.
Features
- Head Diameter: 1.600"
- Stem Diameter: 0.3415"
- Installed Height: Stock
- O/A Length: 4.936"
- Tip Length: 0.250"
- Underhead Angle/Radius: 10° x 3/8°
- Margin: 0.085"
- Seat Width: 0.085
- Top: Flat Face
- XH-428 Stainless Material
- Chrome Stem
- Hardened Tip
- Swirl Polished
- Fully Machined
Benefits
- Superior stainless steel for high-temperature gasoline engines
- Exhaust material XH-428 with double the ultimate tensile strength (at 1500°F) of competitor products
Please note: The provided image 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 intended use, Manley products are sold without warranty.
Before Ordering
〇 About Import Consumption Tax
At Shaft-ya Shopping Site, we pay the import consumption tax incurred at the time of import on your behalf, so there will be no additional charges beyond the total amount paid at checkout.
〇 Confirmation of Compatibility
All product databases are based on North American vehicles (USDM). Please confirm whether the product can be installed on Japanese domestic vehicles (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 investigate for you.)
If you order without confirming compatibility, we cannot accept returns due to incompatibility.
Please note that even if products are sorted by selecting the year, manufacturer, and vehicle model in the tabs on our top page, it does not necessarily mean they are compatible with Japanese model vehicles without modification.
All products have been translated into Japanese using translation software. As there may be confusing expressions, please contact us if you have any questions before ordering.
○ Regarding Delivery
Shipping costs are paid at the time of checkout. Shipping estimates are calculated automatically once 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 US warehouse. Unlike domestic delivery in Japan, international shipping takes about 7 to 14 days, so please order with sufficient time. If you are in a hurry, please contact us in advance to confirm the delivery date. All products are transported via air freight. They are never shipped by sea freight.
○ Regarding Japanese Vehicle Inspection (Shaken) Compatibility
Please note that all products we handle are basically designed and manufactured outside of Japan. They are not adapted to "Japanese vehicle inspection standards," and we cannot provide strength calculation documents for Japanese inspection purposes. Therefore, all parts are sold for the purpose of "use on circuits, private land, or off-road," and please install and use them at your own risk.
○ Regarding Warranty
Please check the contents immediately upon arrival. Since all products are shipped internationally from outside Japan, there may be shipping damage to packaging boxes or the products themselves. We will only handle returns, refunds, or replacement exchanges if you contact us within 7 days of receipt for products with shipping damage, defective products, or items different from what was ordered. Please understand that for products sold through us, warranty handling will be done "only through us." Please note that we do not handle matters through other companies or distributors located in Japan.