[68Timber]

Your info on the seats sounds right. The later high backs that are rounded off at the top used different bases and likely don't bolt up to the earlier floors. Maybe the drivers side does? But the later passenger side front bucket seat will not since it doesn't hinge at the front of the seat base and fold forward like the late 70's/early 80's seats do. Did your 77 have the back seat that folds forward or bolted fixed to the floor?