Set: V8 Diesel Head Gasket Pair Direct replacement for both sides: OE# 12637785 (Left) & 12637788 (Right). Multi-Layer Steel (MLS) construction exclusively for 6.6L Duramax V8 engines.
Precise Fitment: Heavy-Duty Trucks & Vans Fits: 2001-2016 Chevy Silverado HD / For Gmc Sierra HD (2500, 3500),2006-2016 Express / Savana (2500, 3500), 2009-2016 4500 Series Diesel engine only