New seats are in!

Yes, you have to drill new holes if you had a bench seat like I did. I don't know about a bucket seat car. A hook bolt is just that, it is something like an eye bolt except it is a hook. The Mustang seat rails are not like what our old cars had so you have to improvise a little. Mine ended up solid as a rock and way more comfortable that either the plastic racing seats I had or the stock buckets which are very expensive anyway.

Jack