Thanks for the replies. It's helping me validate some additional thinking and research. It must be a common conversion from EVAP to EFI as I found a memo online from Ford who makes my chassis noting that many Ford chassis used for RV manufacture did not come with EFI return lines and any after market conversions would void the Ford Chassis warranty related to fuel lines and systems, .... It's a 2007 so it's out of warranty anyway. The technical installation guide material I found has a picture showing how the return line is set up. And I also found a recommendation from someone who said don't drill into the fuel tank (for lots of reasons) and choose this adapter kit for return line. Moroso 65385 EFI Fuel Return Line Kit https://www.amazon.com/dp/B001GHUP8I/ref=cm_sw_r_cp_tai_LqaYybZZ7CPKD
