I am in need of the bushings that attach the ends of the heater control cable to the heater valve (round stock with hole in side for cable, screw in top to clamp).

Suggestions appreciated.

Cable stops should be available at hardware or auto parts stores. There is one used on the choke assy and islocated justin front of te firewall bracket. This one may be available from our usual suspects.
Alternatively, you can make then. Get a piece of threaded stand off stock at a hardware store drill a small hole in it to accept the cable, then using a Dremel cut it off to the length you want.--Fwiw--Keoke