I also used a mid 70's (78 I think) cable and pedal. I used the one that has three self-tapping screws and screwed it right to the firewall. I had to bent and tweak the pedal rod some to get it just right, but nothing serious. I then drilled a hole in the firewall right behind the upper part of the pedal rod for the cable. I filed it square and until the cable snapped into it securely and attached the other end to the carb. I think it took me longer to type this that to actually do it,
Scott