I just went through this with my truck, in the end I bought a new one from US radiators. It fit perfectly, it looks great and they built it with a "high efficiency" core so I can upgrade the engine later if I want. The 1/2-3/4 ton use a smaller capacity radiator but the same dimensions as the big bolts, so I ruled out using a small truck radiator. I guess if you find a radiator with similar cooling capacity that has the correct size inlet and outlet and they are close to the same locations as the stock one it should work. For me it wasn't worth the work to find one and make it fit. If you have time why don't you try and find someone who can rebuild the original radiator for you. Here is a link to the one I got. It took about 3 weeks to get it.
http://www.coolcraft.com/chevy-truck-1941-46-6-cyl-radiator.html As a side note, a friend of mine got a new radiator from some chinese junk place and it took us hours to get it to fit the truck, these guys make the radiators here in the U.S. with american parts and american workers and it dropped right in. Good luck, Rob
