My '46 pickup has a late model tank but using original sender and gauge. Made the sender fit the new tank (extended the float arm and used a new brass float). Also used this high tech 12 volt conversion item from Chevs of the 40s, part #1119004 to protect the gauge. So far no problems 10 years plus now.

Jim, I.I. #173
(It's easier to get forgiveness than permission!)