Thank you very much. It looks like you bolted your muffler hangers on the bottom of the floor. That make a lot more sense. Huge help and very much appreciated.
i don't have the car anymore, otherwise i'd go take more detailed pics for ya.
if i recall, the one side aligns the bracket with one hole that's already there for the factory hanger and then you pop holes for the other two on the bracket. on the other side, there's not a factory hanger (these early cars only came with single exhaust) so you need to pop the holes, but the dimensions are listed on the template. it's a little obtuse, but after staring at it (for longer than i care to admit) it made sense.
you do need to have the rear seat bottom out to make it happen.