Found fix for leaking aftermarket sending units

That was the part that was under the tabs. The taller bent corners are the stops for the ring. This ring was on a 67 tank. Possibly there was a change made to the stampings at some point in time.

All i know is the aftermarket ones dont lift as high as these points do, and probably dont exert enough pressure against the gasket. Phoo phoo it if you want, i plan on using it.