Since the IH Truck factory is here in Springfield, Ohio, I have two places you might check.
Walt"s Auto Parts
Springfield, OH 937-525-0000 Since IH Trucks are popular here they may have more IH"s than others away from here.
Super Scout Specialists
Very knowledgeable folks who sell a lot of IH Scout and Light Truck parts. They have many contacts and sources for parts.
Good luck, Bill