Shop By Vehicle
Top Categories
All Categories

Top Categories

All Categories

Hi, ! (Not you?)
My Account
Track Order
Manley 11553-1
Representative Image
Product images may differ from actual product appearance.

Manley Severe Duty Exhaust Valve Big Block Chevy


Estimated to ship directly from the manufacturer on 12/24/18

Manley Severe Duty Exhaust Valve Big Block Chevy $34.99
Out of stock
Severe Duty Exhaust Valve
  • Big Block Chevy
  • 1.720'' Diameter
  • 3/8'' (0.3715'') Stem Diameter
  • 5.354'' Overall Length (Stock)
  • Stainless Steel
  • 1/pkg.
  • Manley 11553-1 Details

    Exhaust Valves

  • 1.720'' Valve Diameter
  • 3/8'' Valve Stem Diameter
  • Type: Exhaust Valve XH-428 Material
  • Head Diameter: 1.720''
  • Stem Diameter: 3/8'' / 0.3715''
  • Installed Height: Stock
  • Overall Length: 5.354''
  • Tip Length: 0.220''
  • Underhead Angle / Radius: 10° x 3/8''
  • Margin: 0.065''
  • Seat Width: 0.100''
  • Top of Head: 6° Dish
  • Weight / Grams: 122

  • Specifications:

    Manufacturer's Part Number:

    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.

  • 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
  • 5/16'' stem valves are ONLY available with Bead Loc keeper grooves. Bead Loc valve locks are REQUIRED.

  • Some parts are not legal for use in California or other states with similar laws / regulations

    Motor Vehicles

    WARNING: Motor vehicles contain fuel, oils and fluids, battery posts, terminals and related accessories which contain lead and lead compounds and other chemicals known to the State of California to cause cancer, birth defects and other reproductive harm. These chemicals are found in vehicles, vehicle parts and accessories, both new and as replacements. When being serviced, these vehicles generate used oil, waste fluids, grease, fumes and particulates, all known to the State of California to cause cancer, birth defects, and reproductive harm.


    WARNING: Some dust created by power sanding, sawing, grinding, drilling, and other construction activities contains chemicals known to the State of California to cause cancer and birth defects or other reproductive harm. Some examples of these chemicals are: lead from lead-based paints, crystalline silica from bricks and cement and other masonry products, and arsenic and chromium from chemically treated lumber. Your risk from exposure to these chemicals varies, depending on how often you do this type of work. To reduce your exposure, work in a well-ventilated area and with approved safety equipment, such as dust masks that are specially designed to filter out microscopic particles.

    Electrical Cords

    WARNING: The wires of these products contain chemicals known to the State of California to cause cancer and birth defects or other reproductive harm. Wash hands after handling.