Thanks Denny for the great info. but on my flathead I only have one hole for one sending unit and the sending unit has two flat pieces of metal coming off of it and at the top of each piece of metal is a small screw. Do I have the wrong sending unit? Is the one I have meant to be with a duel type? will the one I have work if it is by itself and it is not faulty?

Thanks again for all the great info.

Tim