Bucket Seat Floor Hole Diameter

I am changing out to bucket seats on my 72 Grabber. What is the stock hole diameter size in the floor. Also, please verify the following measurements:

side to side 13.25 "
front to back 12"

Lastly, am I correct in assuming the outer holes for the bench seat are to be used for the bucket seat?

 

There are dimples on the floor pans where the holes would have been drilled at the factory. Bucket seat cars came with a welded bracket on the floor pans for the inner seat support, bench seat cars don't have this. The outer holes are the same.

 

are these stock...buckets and rails...?

frank

 

The bucket is out of a 72 Maverick. It has the rails but there are no spacers. It appears that the inside front mounting area is slightly lower than the ousde. The inside rear is much lower by a good one inch or so. The studs were very long so I am wondering if there is something else that goes underneath the rails.

 

The welded in seat mounts go under it on the bottom of the floor pan. That is why the studs are so long.

 

i thought they were longer because they have 2 ...stands...they sit on, that would require a longer bolt.

...Frank...