What do you think about seats

Most likely not....I put Neon Buckets in my 64 Dart using the stock seat brackets adapted to the new seats. That made it easier keeping them level because the floorboards vary in depth from side to side.

The floorboards being all over the place is why I made custom brackets for these.
They were designed for a 100% flat floor.
It's just a little measuring, cutting welding, drilling, painting bolting and redoing a few things again along the way. :D