I have a 1960 F100 truck with a mid 60's engine. I've just got it and was about to move it when the accelerator cable goes limp. Limp where the pedal is and then doesn't seem to come out the other side! Where does it come out of the firewall on the engine side?

 

Looks like it has been routed thru the firewall almost behind the engine and just below the valve cover. It is the black cable housing about 3/8" thick that comes from almost behind the engine, makes a loop over the master cylinder and then heads to the braket next to the carburator. If your pedal is limp, the cable inside the housing may well be broken or you may luck out to find it unhooked.