Just an FYI for future reference, being that it is a GM 350 engine, the gasket you needed can be purchased at local auto parts store. I fill my engine block with RV marine anti-freeze as part of the winterization process via the thermostat housing and buy the gasket for $1.25 at Fleet Farm. I would think they might have the rubber seal as well. I would stick with an OEM part though for the thermostat itself. I can get you the Stant part # if interested. Might save you a drive and some time, should you need one again.