front bucket seats on '68 Barracuda

I put hardwood spacers under the tracks, similar to hockey sticks. The bolts of course were too short. After removing the swedged bolts, I installed regular HH bolts with flat washers on both sides of the track-bracket,and clamped it all together with a HH nut and spring-washer. Then I drilled holes in my wooden spacers to receive the nut and washer. And finally reinstalled the factory nuts underneath the floor. I used long enough bolts to allow for final attitude adjustment, for which I used quite large and thick farm-use flat washers between the spacers and the carpet.
>In another car I procured a 1/4" thick rectangular aluminum plate to span all the holes. I leveled the plate in the car with those same farm-use washers. Finally I dropped the seats thru properly located holes in the plates, and thru the floor,and secured them with the factory nuts. There was just enough stud protruding to get the job done.