There doesn’t seem to be a lot of information out there about these trucks, but from what I could gather from a little Google searching this is an International Cargostar, which has been equipped with a concrete mixer. Wikipedia says the Cargostar was produced from 1970 through 1981 (though unfortunately there’s no source listed to verify that). From Google image searches for various years of Cargostars, it appears that International redesigned the front of the truck for 1974.
This one was just barely visible over the wall of a yard where several more recent concrete mixers and other heavy equipment is stored.
Old Car Hunt 