parking brake cable question

[hfd410]

I put all new cables on my 71 SWB. My question is on the front cable. I snapped it into the frame and ran the cable thru the firewall grommet and attached to the pedal lever. My question is, is there a clamp or something that clamps the cable down to keep it from just pushing thru the grommet? When I depress the pedal it just pushes the whole cable thru the grommet, not just the inner cable, and bows it in the engine compt between the firewall and frame if that makes sense. Any help appreciated.