oiltank & muffler ?

[bossladys 911]

I have a 73 that I need to remove the oil level sender from . I have tried all positions with no luck after removing the nuts and circular flange. The tank is out of the car
I also wonder if the flat seam on my exhaust silencer sits on top or below against the muffler mount that attaches to the engine .The mount has 2 right angle tabs where the muffler straps attach .
Thanks