How about the flashers? Check turn signal switch assembly in column. Also all those lights go through the headlight switch. The rheostat in that switch goes bad after 40 years. Also you might check the wires under the sill plate on the drivers side, could be a short in there.
chevy runs deep, Don't step in chevy!
289 - Holley 4150 570cfm; Performer intake; mild cam; MSD HEI; 302 heads; Roller Tips; Hedman Tri-Y headers; H-pipe w/Flowmaster 40's; 9 in posi 3.50; 205/50-17F; 225/50-17R.