24" or 36" 318 throttle cable?

the linkage has two hex shaped nuts that thread onto a steel bar. The problem i am facing is that neither fit through the throttle pedal assembly. I called my local car parts store and they stated that i don't even need to secure the cable to the firewall. I played around with it a little more just now and it clearly is not working properly while being fastened to the carburetor side in the bracket. Just for reference, the clamp on the firewall side looks identical to the carburetor side only no linkage on the end for the throttle body.