Designed with a combination of shorter durations and higher lifts to offer the advantages of a broad torque output through the entire rpm range. Designed for hydraulics, but could be run with solids. Grind #1 is the low-compression version of an “A” grind cam for 74″ and 80″ models. Made in the USA. On late ’77 and later engines, the pitch diameter on the camshaft, pinion gear and breather valve gear was changed. These components are not interchangeable with earlier style components unless replaced in sets only. Late ’77 and later gear sets are identified by a circular groove machined in the outer face of the cam gear..