I have a 72 PX-10 that I was given from the original owner. He replaced the original 27" rims with 700c rims laced to the original hubs, The bike is otherwise stock. The brakes reach the 700c rims and there are no fitment issues. As the frames have lots of tire clearance you could even go with a little wider rim for a little more tire volume if you want that. Doing it this way will not require changing your rear hub spacing on your frame or any other drive line changes.
Your cost is just rims and spokes, and a bit of labor at your local bike shop if you are unable to lace the wheels up yourself. You could even keep the old rims/spokes in case you ever want to sell the bike to someone who wants the original wheel set up.
Last edited by bikeaddiction1; 03-29-20 at 08:34 AM.
Reason: ad comment