I recently bought a 1970 Chevy C10 Longbed fleetside pickup.  Does anyone know of a manufacturer of plastic bedliners for such an animal?  Can a bedliner from another year be modified easily to fit?  I don't want a spray-in liner. If I can't find a liner, then I will put a mat in it....but I don't like the fact that water can get underneath it....the truck is rust-free and I would like to keep it that way if possible. Thanks!  Jake