Howards Cams Street series retrofit hydraulic roller lifters are designed for street performance enthusiasts who want to upgrade to a hydraulic roller camshaft. They are manufactured to fit early or late model blocks, including blocks with tall lifter bosses. Howards Cams uses cold form technology to shape their bodies for durability. The lifters are then carbonitrided and tempered for hardness. They also feature hardened and tempered steel alloy roller wheels, heat-treated stainless steel cross bars, and high-alloy steel tie bar buttons. Howards Cams Street series retrofit hydraulic roller lifters are specifically designed for street applications up to 6,500 rpm.