Javier, it's hard to help without pictures.

If the mounting frames do not line up, most likely you have a seat from another make. From what has been discussed, the seat mounting frames are the same and they do exchange position with each other.
The seats fit from 1947/1959 GMC/CHEVROLET suburban. The information can be found on this
[font:Arial Black]previous topic[/font] There are some measurements that should help you.