Complete Top-End & Ring Bundle: OEM Matched Includes (1) Cylinder Head / Upper Gasket Set and (4) complete piston ring sets, enough for all 4 cylinders on Cummins 4BT engines.
STD 102mm Piston Rings:  OEM 3802421 Ring sets are Standard (STD) size, 102mm bore, designed for Cummins 3.9L 4BT engines using standard pistons. Ideal for rebuilds without cylinder overbore.
Upper Gasket Set: OEM 3804896 Head gasket kit includes critical top-end sealing components required for cylinder head service, valve work, or gasket replacement on Cummins 4BT diesel engines.
Fits Cummins 4BT 3.9L Applications: Compatible with Cummins 4BT 3.9L 4-Cylinder Diesel Engines, including 1989–2002 Dodge Ram 2500 & 3500 truck replacement applications using 4BT conversions or industrial setups.
Fitment Verification Recommended Before Installation: Fitment depends on engine configuration and bore size. Please confirm 4BT 3.9L, STD 102mm bore, and OEM references 3802421 / 3804896 before installation. Contact us if you need help verifying.