Part# ST2015 - Yella Terra Street Terra pedestal mount roller rocker set to suit Ford 429, 429-BOSS and 460 V8 engines commonly referred to as the 385 family of Ford big block engines or the Poly Angle big blocks. Direct bolts on with no machining required. Economically priced, entry level rollers that have a strong vacuum die formed light weight arm designed for high performance street and budget race applications that do not have excessively high valve spring pressures. For use with hydraulic camshafts. Includes pedestal mounts 5/16 UNC, adjustable valve lash on tail of rocker arm [push rod side], with a rocker arm ratio of 1.72 : 1