You can find a club that specializes in just about anything. Along with the internet, I'd get a copy of the latest Hmmings Motor News and search for a club specific to International Harvester.

With these trucks being orphans, you'll have the same problem as someone rebuilding a Studebaker or Hudson. Not impossible, but patience is the price of having something different.

That truck, as long as all of it is there, is probably worth between $1000 and $3500 depending on it's condition.