20-21100 KPMI, valve spring kit. .600" lift. Aluminum top collars

This Kibblewhite valve spring kit is designed specifically for late 1979 to 1984 Shovelhead engines looking for a performance edge. Sold as a complete kit, it includes high-quality chrome silicone wire springs that have been shot peened and heat treated for maximum fatigue life. The inclusion of lightweight aluminum top collars helps reduce total valve train mass, making this an excellent choice for high-lift racing builds up to .600-inch valve lift. You get the springs, upper and lower collars, and valve keys needed for the job, though please note that valve guide seals are not included. With a seat pressure of 152 lbs and open pressure of 387 lbs at max lift, this setup provides the stability required for aggressive cam profiles.