Sealing transmission pan

This is what I use. They are also on e-bay, and Amazon. Reusable Transmission Pan Gasket | Power Driven Diesel
EDIT: There is also the same type gasket for the 904 based transmissions. The 904 gasket can be used all the way back to 1960. 1960-1962 require the newer filter and oil pan. Also on the cable shifter trans, if using this gasket, the gasket covers access to one of the bolts for the park cable housing. This does not allow removing the housing without dropping the pan.