I'll start out by saying that I think the '68 choke thermostatic spring and choke rod are the same as the '67 (somebody correct me if I'm wrong). For my '67 I purchased the thermostatic spring new from Napa back in 2001 and found a used choke rod off of the Camaros.net classifieds. I'm not sure if the spring is still available new, but the rod back in '01 was only available as a used part.
The spring mounts in a depression of the exhaust manifold with two screws below the carburator. Both of my screws had rusted and fused to the manifold, so I had to have them drilled out and re-tapped. My choke rod had also rusted away so that the key that holds the rod into the spring was gone.
Good Luck,
Dan
