Hey Dave....was just checking out Ebay....item #150124834463....54 Chevy pickup with a fuzzy picture of a bench seat out of a 1989 Chevy Cheyenne. Check it out as this may (or may not) be the Holy Grail!!!!
The 3rd row seats are pretty thin.....I actually put it into the truck on mock up blocks but it was just plain butt ugly. Think it was out of a WindStar or maybe an AeroStar FoMoCo. The front of the seat measures 53 inches but the back pivot measurement is 56".
With your lower support removed you should be able to use a regular full floormount. My LeSabre has some awesome leathers but they are only 51" wide. They are fairly low-backed which I like.
Dave
