if the vertical gallery below the sender threaded opening is bigger dia than the opening itself (which it likely might be if it was drilled up thru the bottom (& likely it was) then you might open up/tap that sender threaded opening there at the top for a larger fitting for your line then use common plumbing NPT reducer bushing and a T to screw the sender back in. Just thinking out loud. EDIT Just hit me, We plumbed an accumulator T'd to the SB oil sender (no redrilling/as is) & it primed in less than 2 minutes if that