Severe Duty Exhaust Valve Small Block Chevy

Name: Severe Duty Exhaust Valve Small Block Chevy
Brand: MANLEY
SKU: 660-11543-1
Price: 37.64 USD
Availability: InStock

^$37⁶⁴

Ships on Oct 02, 2026

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Exhaust Valves

1.600'' Valve Diameter

11/32'' Valve Stem Diameter

10° x 3/8'' Underhead Angle/Radius

Small Block Chevy
1.600'' Diameter
11/32'' (0.3415'') Stem Diameter
4.911'' Overall Length (Stock)
10° x 3/8'' Underhead Angle/Radius
Stainless Steel
1/pkg.
Type: Exhaust Valve XH-428 Material
Head Diameter: 1.600'
Stem Diameter: 11/32' / 0.3415'
Installed Height: Stock
Overall Length: 4.911'
Tip Length: 0.250'
Underhead Angle / Radius: 10° x 3/8'
Margin: 0.060'
Seat Width: 0.100'
Top of Head: 7° Dish
Weight / Grams: 95

Standard Straight Valve Stem Design

Manley Performance is indisputably a leading manufacturer of performance and racing components in the world. The reason for Manley's overwhelming success is simple: Quality. Manley offers the best materials in the industry - exclusive materials that other manufacturers do not possess. Manley's valve stems are hard coated with .0002'' thick chrome rather than a few millionths of flash. Manley's hard valve tips are superior to competitors' puddled ''stellite'' which can crack and erode off the stem. Manley's valve head and under head shapes have been in the forefront of the quest for improved flow since the late 1960's.

The Severe Duty series valves are Manley's signature pieces in the performance and racing industry. Exhaust valve material XH-428 and intake valve material NK-844 is offered by no competitor in the world. And no pair of materials show such clear dominance over all others. Ultimate tensile strength of XH-428 at 1500°F is nearly double the competitors' EV-8. At 1000°F the Manley NK-844 displays more than four times the ultimate tensile of the competition's best intake material. Further proof of the superiority of the Manley Severe Duty valves is evident in their comprehensive fatigue tests. In normal operation where valve float is non-existent, a valve will experience 20,000 to 25,000 lbs. of applied stress. However, when valves bounce on the seat the stress immediately soars to 40,000 to 60,000 lbs. Manley exhaust valves (at 40,000 psi and 1400°F) ran to 100,000,000 (one hundred million) cycles while competitors' offerings failed at 100,000 cycles. That's 1000 times better fatigue life.

Features:

Superior Stainless for High Temperature Gasoline Engines
Exhaust Material XH-428 with Double the Ultimate Tensile Strength (at 1500°F) over the competition
Chrome Stems and Hard Tips
Swirl Polished and Fully Machined
Severe Duty (Straight Stem) and Severe Duty Pro Flo (Undercut Stem) Shapes Available
7mm and 5/16'' stem valves are ONLY available with Bead Loc keeper grooves. Bead Loc valve locks are REQUIRED.

Click Here for Manley's Pro Flo Valve Shape & Info

Click Here to See Valve Buyers Guide