I am in the process of converting my bench seat to bucket seats. I have the adapter brackets and am trying to figure out how they work best. I have the pass seat sitting in the car with the inboard new bracket attached with the 2 outer front and back bolts in where the old bench seat brackets were attached. On the inboard side by the hump I have the new bracket with the raised end towards the front of the car and the flat section in the back. It looks to me that when everything is bolted down that the right rear outer mount needs to come up about an inch to make the seat level. Do you need to use a spacer on where the existing outer hole is? I thought that with these adapter brackets that all that was needed was to weld the new inner brackets in and mount the seats and be done with it. Am I missing something?

Here is what I did on my 64. I made sure the seat brackets were even and locked. I then bolted the inner adapter bracket to the seat and then bolted the seat to the outter bolt holes... a little stretching of the seat brackets or wallowing out the holes will do the job. I then marked the where the inner bracket needed to go pulled it out and tack welded it in. Double checked my placement by refitting the seat. I only used the one piece inner brackt I didnt have any others and the seat sat just fine and level.

It's been a long time since I did mine but I think I shimmed the rear outer corners with washers to level the seat. Not quite sure if it was an inch off but I do remember having to shim it.