Crane Cams professional quality, Pro-Series rocker arm studs feature an extra large radii for reduced stud flex, even with today's extreme valve spring pressures and high rpm racing engine operating levels. Our Pro-Series rocker studs are precision manufactured from 190,000 P.S.I. strength alloy steel material with rolled threads, and precise top-to-bottom concentricity. These are state-of-the-art items designed and priced for those seeking the highest quality parts available. The 99151 stud has a longer than normal unthreaded portion in the top section, providing superior support and stability for the rocker arm fulcrum. Review products and applications. 7/16" Rocker Arm Studs Set/16 99151-16$80.00 7/16" Rocker Arm Studs Set/16 99153-16$84.80 3/8" Rocker Arm Studs Pkg/2 99154-2$20.00