I'm in the process of installing a new camshaft (Performer Plus). I want to put new valve springs in while I'm at it. Do I need to put air pressure on the valves? Don't have an air compressor. Will I screw something up if I just remove the valve springs without air?

Only problem with stuffing rope down the hole to keep the valves in place, is wondering if you put enough to do the job. If it ain't enough, you're going to play hell getting the retainers and keepers back in place.
You know , like one of those Ingersoll-Rand industrial types on a 4 wheeled buggy ?