Originally Posted by
devinfan
Thanks for all the help! The freeweheel is currently 13 - 23, which I thought was kind of big already. If you all think the rear derailleur (it is a steel Campy Record, not NR) can handle a 28 tooth rear then that is what I'll do! I wasn't sure it could because it is short cage and almost 50 years old.
Well, Mr. Corncob, someone who knows more can chime in, but I'd be surprised if it couldn't handle at least a 26 if not 28. Bigger than that, I wouldn't be surprised to hear some Italian expletives coming from the rear.
I'd find (maybe borrow?) an appropriate freewheel and give it a test. You'll probably need a new chain, but that's not a big deal.