Certainly not worth $25 and the auction isn't over. What you need to look for is set up that has the pedal shaft pivot like in the Chevelle. That part will bolt to the firewall in the 64-67 Chevelles with no modifications. You will also need to get the bracket to secure the cable onto the manifold and make a square hole in the firewall to secure the other end.
Here are some old photos I took when I was converting my 64 to a throttle cable. I was using parts from a 68 Camaro, but I believe they are the same as the Nova. Sorry for the picture quality, but these are scanned photographs (before the digital camera age
In this photo is the stock 64 set up and it had bushings in it.
This one is from the 68 Camaro .The e clip holds the rod into the pivot bracket
This photo shows the difference in the length of the rod that goes in the pivot bracket. The Chevelle arm on the left goes all the way thru and the lever for the carb rod secures it in place. The Camaro/Nova rod is retained by an E clip.
These are the brackets side by side. The Chevelle is metal and the Camaro is plastic. As you can see they are identical except for the material.