HEAT-TREATED STEEL CONSTRUCTION – Manufactured from premium steel for excellent strength, wear resistance, and long service life. RESTORES VALVE TRAIN PERFORMANCE – Helps maintain proper valve movement, reducing wear while restoring smooth engine operation. DIRECT REPLACEMENT DESIGN – Precision-machined to meet factory fitment for straightforward installation during engine repairs or rebuilds. IDEAL FOR REBUILDS & MAINTENANCE – Perfect for replacing worn rocker arms during cylinder head service, engine overhauls, and routine maintenance. Replacement For: 1983 – 1998 3.9L 4BT Cummins I4 Diesel Engines.