I am desperate for info on search for a metal gasket. the car is a 1980 buick riviera 3.8liter v-6 turbo engine.I have recently puchased a rebuilt turbo,no gaskets were included. I found a gasket kit p/n es72508.It has most of the gaskets.The one gasket not included is a metal gasket 4 bolt holes offset with large center opening.Thisgasket goes between the exhaust pipe and turbo unit.Where can I find one,any and all help is appriciated. THANK YOU