There are two fusible links at the starter solenoid. If you blew one of them you had a direct short somewhere. A fusible link was smaller than the rest of the wiring so it would fail first and protect the main harness. 1967_Buick_Chassis_Service_Manual_-_Section_12C.pdfThanks to all of you. The battery cables are secure and well grounded. I can't figure out from the wiring diagram how voltage gets to the fuse block and whether a main fuse is there. I was trying to start the engine when everything went dead.