Tank unit for gas guage
 

After searching parts suppliers with no luck. Is this a part that has to come from a ford dealer?

Fuel gauge sending unit. I actually just called autozone today for a price. they can get one, but the have to order. Think he said it was $90 or so.
Would suggest replacing the lock ring as well, they tend to rust up pretty bad and you'll end up bending the crap out of it. $20

Or look here...

http://www.latemodelrestoration.com/index.aspx

They have new and non OEM plus lock ring