2005 Scion TC seats in my 68 Dart.
Rather than build brackets which would have raised the seats an inch or two, I chose to modify the floor to fit the seats. I cut the bench seat humps out of the floor and replaced them with flat sheet metal. And welded in reinforment plates to the floor (top and bottom)
Very comfortable, and for accessing the back seat, the seat backs fold forward, and then the seat slides forward, makes for easy access to the back seat. Seats cost me $200 buck off craigslist.