Clutch rises 3 to 4 inches before the truck starts to move

What is your question?

When I let out the clutch out on my 77 f250 there is 3 to 4 inches of rise before truck moves and the rpms on the highway seem to be high like I need to shift to a higher gear even though I am in 4th. Problem start about 25000 miles after engine swap. The clutch was replaced at same time as engine.