Maybe this has already been completely resolved. After doing some checking I believe #3887023 Heat valve was used from '67 to '69 on all Smallblock Camaros. I am seeing also that it is called for from '64 to '72 on Smallblock Chevelles and Novas. As for orientation pics. in replies #30,#33, and #45 all seem to be the same, on the outside parallel to the frame, with the heavy "weighted" end of the lever pointing back towards the Firewall. Jerry McN. also has a Blue unrestored '67 Z28 on his website that appears to have this same orientation. Maybe he can chime in, or give him a call.