Sorry I'm late to the party, Jeff... I don't often read the board these days, not enough time. Shoot me an email if you have a 603 question, though. Anyway, as you found out, for the 124/603 vac pump, the radiator can stay in place - as long as you remove the fan & clutch. Draining a gallon of coolant so the upper rad hose can come out makes things even easier.
I assume you've seen my vac pump explosion saga? And I had one of the new-style pumps, too!
http://www.peachparts.com/shopforum/showthread.php?t=231260
