[Frank Messina]

Bob,
We are talking about the same thing. As you probably know, on most garden variety Holley carbs the idle air bleeds are not removeable. This feature showed up more recently on the high end carbs. Prior to that, you had to drill the throttle plate with a small 1/8" hole to get more air. Drilling the idle air bleeds and the high speed bleeds was always a tuning step best left to the pros.

Scott,
If you're going back to the 73's on the secondary, put the 6.5 power valve back in there. Then verify the opening point with your vacuum gauge as outlined previously ( 1/2 idle vac). I've set up Holleys both ways and tricked out beyond description and never found there was any advantage to removing the power valve. You can do it either way, it just doesn't seem to matter. The newer carbs all have a check valve in them to prevent power valve blowout in the event of a serious backfire and is easily retrofitted to older carbs.
Frank