I just replaced the fuel tank in 46' pick up with a reproduction tank from American Classic Truck Parts.
It needed a little adjustment of the flange corners and some slight grinding of the flange in places for a good fit but all in all it seems to be well made. I also had to drill an additional 1/2" hole in the bottom of the truck to accommodate a pipe port in the tank which would not allow the tank to lay flush on the floor. I'm pretty happy with it. About 375+ shipping.