You will want the float to face towards the right side of the tank. I ran into this with on a 220SE ( 128 Cab. ) where we used a 190SL sender. The float was hitting the flower pot and giving false 1/4 full readings when it was actually empty. In this case and to fix that problem, we drilled a couple of extra holes in the flange of the sender so it could be indexed in the opposite direction from what an original sender would have been mounted.