Well, the curved 8-wire connector on the column and the flashers all work correctly, thanks to all who helped. In the course of working on the speedo, I disconnected everything from the instrument cluster, and even labelled the wires to the ammeter. When I put everything back, I nearly burned the truck up. Obviously I screwed up, and it involves the four wires to the ammeter.The four wires are one to the alternator (one-wire alternator), one to the BATT screw on the ignition switch, one to the big lug on the starter, and one full-time hot to the light switch and horn. I know these are connected as two pairs (not one and three). Which two go to the discharge side of the ammeter (left), and which go to the charge side (right)?

1957 Chevrolet Pickup Truck