West Marine!
I replaced the fuel sending unit in my 81' Hunter 30 with a universal guage from West Marine. I took the old one out and took it to West Marine to make sure the bolt pattern would match up. I also found that while the screw holes look equally spaced, I had to rotate the sending unit until all 5 holes lined up properly, so you might want to get all the screws started before tightening down. I did have to "cut to fit" for my tank depth, but the instructions were easy to follow. My fuel guage has worked well ever since.
