Manley 12336-8 Severe Duty Pro Flo Intake Valve 2.080" Head Diameter .3133" Stem

With a 2.080" head diameter, .3133" stem diameter, a +.100" oversize grind, and a 5.035" overall length, these valves are engineered for bracket racing, oval track competition, and high-performance street applications.

Constructed from Manley's proprietary NK-844 stainless steel alloy, the intake valve material delivers over four times the ultimate tensile strength of competing intake valve materials at 1,000°F — providing unmatched reliability under extreme heat and stress cycles.

Key Features:

• NK-844 Intake Alloy: Proprietary stainless steel with exceptional high-temperature tensile strength
• Chrome Stems & Hardened Tips: Chromium-treated stems (.3133" diameter) and hard valve tips for extended service life
• Swirl Polished Under-Head: Reduces air turbulence and drag for improved airflow and combustion efficiency
• Fully Machined Combustion Faces: Precision-machined for consistent sealing and optimized combustion
• +.100" Oversize: Provides additional material for head porting and custom fitment
• Proven Fatigue Resistance: Engineered to withstand 40,000–60,000 lbs of stress during valve float events

Specifications:

• Head Diameter: 2.080"
• Stem Diameter: .3133"
• Oversize: +.100"
• Overall Length (O/A): 5.035"
• Tip Length: .260"
• Valve Type: Intake
• Material: NK-844 Stainless Steel

Installation Note: Manley stem sizes are .3133" (intake). All cylinder head guides should be checked and properly sized by a machinist to achieve correct stem-to-guide clearance. Compatible valve locks include Manley P/N 13098-16 (7°) or 13153-16 (10°) depending on spring and retainer selection.

Manley's Severe Duty Pro Flo intake valves are ideal for naturally aspirated, forced-induction, and nitrous-assisted SBC builds where valve durability and airflow efficiency are critical.