The "C" knob. From steering column going left. Choke, wiper then light switch. From the light switch, go left 3 and one half inches, then down two inches. There is the location of the "C" knob. It's on the dash, but not on the instrument panel. And from all apperances, it is original equipmemt. Also, I checked with Mile Marker, they do not list a locking hub for a '64 Burb. LMC has a hub listed that works for a 60-66 K10, but when I phoned them, they could not tell me if it would work on a Burb. They suggested I ask a local mechanic. Right! A mechanic in Buffalo, Wyoming is going to know if a hub that works on a '64 pickup will work on a '64 Burb. What with so many '64 pickups and Burbs running around Buffalo, Wyoming. I think not. I have e-mailed everyone at Stovebolt with a photo of a Burb and had no response. Someone out there has to know where I can find hubs.