Thanks to all for your comments. I have the original glass tail lamps with two sockets each. One socket(single element) handles the aftermarket turnsignals. The other socket I replaced with a dual element. The wiring harness only carried one wire for brakes and one for tail lights and there were two wires one for each side for turn signals and that was never a problem. So I ran a wire from one side to the other to bring over the other tail lamp signal and the brake light. All works perfect and the only issue I have is the bulbs are a little larger/longer than the tail light housing can accomodate so I had to do a little adjustment. The other porblem was the bulbs they sent were 6 volt and lasted about 10 seconds.

Thanks to all for comments.

1953 GMC 1/2-Ton Pickup