COMP Cams - 1831-1Ultra Pro Magnum XD Rocker w/ 1.6 Ratio for Ford 289, 302, 351W w/ 3/8" StudMachined from 8650 steel with a billet pushrod seat insert, these Ultra Pro Magnum XD rockers can handle up to 1,000 lbs of spring pressure. This 1831 rocker...