Base Gasket (4 Hole) 4150 gaskets are a great way to ensure a leak free seal. Gaskets are made in-house by APD using the same corrosion resistant, anti-stick MP15 material that we use in our carburetors and fuel systems.Gaskets are made in-house by APD using the same corrosion resistant, anti-stick MP15 material that we use in our carburetors and fuel systems.