Here's a link to a recent auction with some similar signs, although these signs had their frames and poles sold with them. There isn't a tremendous amount of value for the Ford signs because of the enormous size and limited ability to display. The more pictures of the different types of Ford signs you have, the better, as different styles might have different values. I'm actually looking for a replacement for my large "FORD" section, as a recent windstorm broke out that panel in my sign. Too bad your all the way out in North Dakota.

https://www.proxibid.com/Joe-R-Pyle...nt-catalog/143442?srch=&srchloc=true

https://www.proxibid.com/Art-Antiqu...d-Cars-with-pole/lotInformation/41837919

The "plastic-like" panels are made of a material called Lexan. The Standard oil sign would have more value if it wasn't so faded. "Plastic" or Lexan signs are growing in value, but are way behind the prices of porcelain signs, as a lot of collectors see little value in them or think of them as entry level. Also, with the Standard sign being so faded, it's unable to be restored. The flame section shown by itself probably has more value than the large sign pictured that it goes on.

The Champion spark plug cleaner you can find for sale at a large swap meet for $100-150.