I used a rear bench seat from a Dodge Darango for my Huckster Van, cost of $25 dollars from a junk yard, seat belts were attached to it also. It was Red, and I used Ritz Clothing Dye to color it Black. The width of the seat is 41". Go to post #19 in the link below to see more Photo's.
https://www.fordbarn.com/forum/showthread.php?t=4075 plus more Photos in my Profile showing it installed.