Manley Chevy LS-3/L-99 Small Block Severe Duty Exhaust Valves (Set of 8)

SKU: MAN11661-8

Valves

MAN Severe Duty Valves

Manley Performance

Manley Chevy LS-3/L-99 Small Block Severe Duty Exhaust Valves (Set of 8)

SKU: MAN11661-8

Valves

MAN Severe Duty Valves

Available from MFR. This item is available from the manufacturer's distribution centre. The dispatch timeframe shown is an estimate based on historical order processing and release times for this part. This item is not held in our own warehouse, and actual dispatch timing may vary depending on manufacturer workload and logistics 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 Exhaust Valve

Data: v4.2 - Upd: 2026-09-29 08:00:17

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: 11661-8
Product Attributes - Part Type: Valves
Product Attributes - Product Line: Manley Race Series Stainless Steel Valves
Product Attributes - UPC: 807298051451
Product Attributes - Valve Position: Exhaust
Product Attributes - Exhaust Valve Head Diameter (in.): 1.590 in.
Product Attributes - Exhaust Valve Head Diameter (mm): 40.386mm
Product Attributes - Exhaust Valve Stem Diameter (in.): 0.314 in.
Product Attributes - Exhaust Valve Stem Diameter (mm): 7.96mm
Product Attributes - Exhaust Overall Valve Length (in.): 4.923 in.
Product Attributes - Exhaust Overall Valve Length (mm): 125.044mm
Product Attributes - Undercut Stem: Yes
Product Attributes - Swirl-Polished: Yes
Product Attributes - Valve Tip Length (in.): 0.160 in.
Product Attributes - Valve Tip Length (mm): 4.064mm
Product Attributes - Valve Material: XH-426 stainless steel
Product Attributes - Lock Groove Quantity: 1-groove
Product Attributes - Lock Groove Style: Conventional
Product Attributes - Approximate Weight (g): 93
Product Attributes - Valve Head Style: 7 degree dish
Product Attributes - Valve Seat Width (in.): 0.115 in.
Product Attributes - Quantity: Sold as a set of 8.

Reference Information

Brand Name/s	Manley Performance
StreetFX SKU	man11661-8
SFX Item ID	4060401
Supplier Item Code	4060401
Manufacturer SKU	11661-8
Manufacturer UPC	807298051451
Alternative References	LS-3/L-99

Compatibility

Application Data

Valve Fitment	Search by engine
Make	CHEVROLET
Beginning Year	2008
Ending Year	2017
Engine Type	V8
Engine Size	6.2L/376
Engine Family	Chevy small block Gen III/IV (LS-based engines)
Valve Installed Length	Stock
Cylinder Head Style (application)	L92

Valve Fitment	Search by engine
Make	CHEVROLET
Beginning Year	2010
Ending Year	2017
Engine Type	V8
Engine Size	6.2L/376
Engine Family	Chevy small block Gen III/IV (LS-based engines)
Valve Installed Length	Stock
Cylinder Head Style (application)	L92