Sierra 18-3855 Head Gasket The Sierra 18-3855 Head Gasket is interchangeable with the following: Chrysler/Force/US Marine 27-820438, GLM 36290, Mallory 9-63800. Each Sierra product meets or exceeds the original equipment part it replaces. Sierra Head Gasket Meets or exceeds the original equipment quality Sierra part number: 18-3855 Interchangeable with the following: Chrysler/Force/US Marine 27-820438, GLM 36290, Mallory 9-63800