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Manley Severe Duty Pro Flo Series Stainless Steel Valves 11840-8 Valves, Intake, NK-844 Stainless, 1.937 in. Diameter, 4.911 in. Length, Chevy, Small Block, Set of 8

SKU: MAN11840-8

Valves

Manley Severe Duty Pro Flo Series Stainless Steel Valves 11840-8 Valves, Intake, NK-844 Stainless, 1.937 in. Diameter, 4.911 in. Length, Chevy, Small Block, Set of 8

SKU: MAN11840-8

Valves
A$589.63
Limited Availability from MFR Limited stock available from the manufacturer's distribution centre. The dispatch timeframe shown is an estimate based on historical orders of this part. This item is not held in our own warehouse, and availability and release timing may vary depending on manufacturer stock movements and processing at the time of ordering.
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Description

Manley Severe Duty® Valves deliver the ultimate in strength, reliability, and high-performance durability. Engineered for extreme gasoline engine temperatures, these valves are crafted from exclusive materials (XH-428 for exhaust and NK-844 for intake), offering unmatched tensile strength compared to competitive alloys. In fatigue testing at 40,000 psi and 1400°F, Manley exhaust valves endured 100 million cycles, while competitors failed after just 100,000, proving a 1,000× longer fatigue life. Each valve features chrome stems, hard tips, and swirl-polished underheads with fully machined combustion faces for superior airflow, efficiency, and wear resistance. Built for those who demand race-winning strength and precision, Manley Severe Duty® Valves set the industry standard for performance and endurance.

Part Type

Engine Intake Valve

Data: v4.2 - Upd: 2026-10-14 10:05:37

Features

  • Chrome stems and hard tips enhance durability
  • Exotic alloys for superior tensile strength, reliability, and longevity
  • Proven fatigue strength for extreme performance
  • Swirl polishing and machined faces improved airflow/optimized efficiency

Specifications

Product Attributes - Brand
Manley
Product Attributes - Manufacturer's Part Number
11840-8
Product Attributes - Part Type
Valves
Product Attributes - Product Line
Manley Severe Duty Pro Flo Series Stainless Steel Valves
Product Attributes - UPC
807298053752
Product Attributes - Valve Position
Intake
Product Attributes - Intake Valve Head Diameter (in.)
1.937 in.
Product Attributes - Intake Valve Head Diameter (mm)
49.200mm
Product Attributes - Intake Valve Stem Diameter (in.)
0.342 in.
Product Attributes - Intake Valve Stem Diameter (mm)
8.69mm
Product Attributes - Intake Overall Valve Length (in.)
4.911 in.
Product Attributes - Intake Overall Valve Length (mm)
124.739mm
Product Attributes - Undercut Stem
No
Product Attributes - Swirl-Polished
Yes
Product Attributes - Valve Tip Length (in.)
0.250 in.
Product Attributes - Valve Tip Length (mm)
6.350mm
Product Attributes - Valve Material
NK-844 stainless steel
Product Attributes - Lock Groove Quantity
1-groove
Product Attributes - Lock Groove Style
Conventional
Product Attributes - Approximate Weight (g)
111
Product Attributes - Valve Head Style
7 degree dish
Product Attributes - Valve Seat Width (in.)
0.080 in.
Product Attributes - Quantity
Sold as a set of 8.

Reference Information

Brand Name/s Manley Performance
StreetFX SKU man11840-8
SFX Item ID 4933149
Supplier Item Code 4933149
Manufacturer SKU 11840-8
Manufacturer UPC 807298053752
Alternative References NK-844

Compatibility

Application Data
  • Valve FitmentSearch by engine
    MakeCHEVROLET
    Beginning Year1955
    Ending Year1957
    Engine TypeV8
    Engine Size4.3L/265
    Engine FamilyChevy small block Gen I
    Valve Installed LengthStock
  • Valve FitmentSearch by engine
    MakeCHEVROLET
    Beginning Year1957
    Ending Year1967
    Engine TypeV8
    Engine Size4.6L/283
    Engine FamilyChevy small block Gen I
    Valve Installed LengthStock
  • Valve FitmentSearch by engine
    MakeCHEVROLET
    Beginning Year1962
    Ending Year1969
    Engine TypeV8
    Engine Size5.3L/327
    Engine FamilyChevy small block Gen I
    Valve Installed LengthStock
  • Valve FitmentSearch by engine
    MakeCHEVROLET
    Beginning Year1967
    Ending Year1969
    Engine TypeV8
    Engine Size4.9L/302
    Engine FamilyChevy small block Gen I
    Valve Installed LengthStock
  • Valve FitmentSearch by engine
    MakeCHEVROLET
    Beginning Year1967
    Ending Year2004
    Engine TypeV8
    Engine Size5.7L/350
    Engine FamilyChevy small block Gen I
    Valve Installed LengthStock
  • Valve FitmentSearch by engine
    MakeCHEVROLET
    Beginning Year1968
    Ending Year1973
    Engine TypeV8
    Engine Size5.0L/307
    Engine FamilyChevy small block Gen I
    Valve Installed LengthStock
  • Valve FitmentSearch by engine
    MakeCHEVROLET
    Beginning Year1970
    Ending Year1980
    Engine TypeV8
    Engine Size6.6L/400
    Engine FamilyChevy small block Gen I
    Valve Installed LengthStock
  • Valve FitmentSearch by engine
    MakeCHEVROLET
    Beginning Year1975
    Ending Year1976
    Engine TypeV8
    Engine Size4.3L/262
    Engine FamilyChevy small block Gen I
    Valve Installed LengthStock
  • Valve FitmentSearch by engine
    MakeCHEVROLET
    Beginning Year1976
    Ending Year2002
    Engine TypeV8
    Engine Size5.0L/305
    Engine FamilyChevy small block Gen I
    Valve Installed LengthStock
  • Valve FitmentSearch by engine
    MakeCHEVROLET
    Beginning Year1979
    Ending Year1982
    Engine TypeV8
    Engine Size4.4L/267
    Engine FamilyChevy small block Gen I
    Valve Installed LengthStock

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