Getting a new one made is not hard, I custom ordered mine from Pegasus Racing (if I remember, total 74" long...). The hard part is getting it in place; since the original rests in a metal tube on the spine--tightly--I replaced completely the metal tube along with the cable. Which means installing the cable, then making the bend in the pipe...
Throttle Cables - Pegasus Auto Racing Supplies
...early reviews of the goose (that 'the throttle cable felt like it was lubricated with gravel') have been in my head since the 80's...! "PTFE lined" just sounds better...