Originally Posted by Dragsix
. . . reinstall using a Rimflex gasket. The Rimflex is a one piece gasket which makes installing it a little easier, and it is a little more forgiving then the stock gaskets . . .

Most likely you are referring to a Remflex manifold gasket?

A lot of vendors are selling that same name/number gasket that looks like this?
The description looks right: "Remflex exhaust header gasket sets feature 100 percent flexible graphite construction that's effective up to 3,000 degrees F, far exceeding any vehicle's exhaust system temperature. They will rebound 30 percent when tightened, creating an optimum seal that eliminates the need for re-torquing. The unique Remflex material has been proven for over three decades in industrial applications, where temperatures routinely exceed 2,000 degrees F. They're designed to crush up to 50 percent, filling uneven header flanges for maximum sealing and eliminating the potential for exhaust leaks. Choose the gasket style and dimensions for your specific exhaust headers."

They also make/market pieces of materials.
These might be handy with "odd GM-truck" applications, like updraft carburetors' manifolds on COEs?

Tim
1954Advance-Design.com
1954 3106 Carryall Suburban
1954 3104 5-window pickup w/Hydra-Matic
The 216 and early 235 engines are not "splash oilers" -- this is a splash oiler.