May sound dumb but restoring a 65 malibu (buckets). The front mounting positions have one "slip" hole for mounting to floor pan. Rear seat track mounting positions have two (side by side) mounting holes. 1) Why is this and 2) which hole should be used to attach to floor pan?
Thanks

The rear outboard holes are for a bench seat.
With a bench---both holes in the bracket should align witn the holes in the floor.

with buckets---the inboard hole in the floor is used with the outboard hole on the seat track.

The front holes---(on factory buckets) should mount to a bracket welded to the floor.
this hole is 1/2" forward and 1/2" inboard of the existing hole in the floor.

I know this applies to 66-72----not sure if the 64/5 is different.
There is a "sticky" on this in the interior forum.

Bryan