It's a pretty easy carb to rebuild; I bought a pair of 40's at a swap meet with the manifolds and linkage to put on a 2.0 bus engine years ago. The rebuild was straightforward and the hardest part was cleaning the smaller passages. I basically disassembled them, soaked the parts in a can of berrymans chem-dip for the weekend, used a brass brush to clean most of it, then used wire drills and compressed air to take care of the passages. Online diagrams made it easy to reassemble.