Manley 12850-8 Severe Duty Intake Valves NK-844 Stainless Steel

Forged from Manley's proprietary NK-844 stainless steel, these valves deliver over four times the ultimate tensile strength of competing intake valve materials at 1,000°F, making them a benchmark choice in the performance and racing industry.

Each valve features a chrome stem for wear resistance and a hardened valve tip for long-term durability under repeated cam lobe contact. The underhead area is swirl polished and the combustion face is fully machined to optimize airflow and combustion efficiency. The straight stem design further enhances durability in high-stress applications.

Key Specifications:

• Valve Type: Intake
• Material: NK-844 Stainless Steel
• Head Diameter: 2.020 in.
• Stem Diameter: 0.3415 in. (11/32)
• Overall Length: 5.015 in.
• Installed Height: +0.100 in. longer than stock
• Tip Length: 0.250 in.
• Underhead Angle/Radius: 10 degrees x 3/8 in.
• Margin: 0.070 in.
• Seat Width: 0.080 in.
• Top of Head: 7-degree dish
• Valve Weight: 113 grams each
• Stem Style: Straight stem

Installation Note: These 5/16 in. stem valves are only compatible with Bead Loc keeper grooves. Bead Loc valve locks are required for proper installation.

Manley's Severe Duty series represents the pinnacle of valve technology for bracket racing, oval track, and high-performance street applications. The NK-844 material combined with precision machining and swirl polishing ensures consistent performance and longevity in the most demanding engine environments.