Most of the used ones out there are probably going to require some work to get reliable connections. I think you should consider Maynards' suggestion and rebuild it yourself. You can usually take the contacts out of the connectors and clean and reform them to make a good connection.
The terminals for the wire used to be available at your local Chevy store. I ordered boxes of 100 of each of the male and female ends that clip into the plastic couplers many years ago. The couplers may still be available from the same source as well.
Make friends with the parts guy. It sometimes takes some dilgent searching. Those parts were used well into the '70's or later.