What is the carb doing that you say it needs to be replaced?
A q-jet isn't that hard to rebuild assuming all of the parts are good. Do a Google search and you will turn up a few helpful links when rebuilding to repair common failures. Debending on what it's doing after rebuild it could be a few issues.
I have also ran into a few that had warped top plates, no way to rebuild that and get a good running engine no matter how hard you try.
Check out these links for some helpful tips: