The other column should work fine but you may have to take the shift lever out of it for it to turn freely. There is actually a cable that goes from the floor shifter to the steering column and pushes or pulls the column shift collar to shift the transmission, you'll see it when you drop the old column out. The shifter does lock out if the ignition switch is off on your car too, i think that started in the late 70's.
as far as the engine in your car. Performance parts are a bit hard to get, but not impossible. the quickest way to really wake it up is going to be cam, intake, and heads swap but you might find it cheaper to drop in a built 350.as the 5.0 engine was never a real runner even hopped up.