Manley Big Block Chevy Severe Duty Stainless Steel Exhaust Valves

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
• 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