Ebay- - - - -"new old stock" from closed down dealerships, warehouses, etc. There are thousands of them there. You don't necessarily have to use the exact part- - - -a choke unloader is pretty generic, and lots of them will work with a little tweaking of the mounting hardware. "NORS" (new old replacement stock) would be another option- - - -parts made by non-GM manufacturers from the same time frame would also be a good choice.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!