Brent Mullins (Jeep Parts) here in Texas has intake manifolds for $55US.
WO A-1166 "Manifold, intake, late type"
Main web page is
http://www.mullinsjeepparts.com/
There are different patterns of manifold depending on year of production and maker so if you want to replace your busted manifold with the correct type for you vehicle, you might need to do a little research. They are all interchangeable though in terms of wartime Willys or Ford production.