2000 was a transition year for Litespeed. That year most of their road bikes had been converted to 1-1/8" headsets but the Classic was an exception and retained the use of a 1" headset. You need a 1" ISO press-in cup type headset and crown race. The cup OD will be 30.2 mm and the crown race ID will be 26.4 mm.

The Cane Creek 110 headset is an excellent one but very expensive. Their 40-series are extremely good and a lot less costly. I have a 40-series on my 1996 Litespeed Catalyst that I converted to a threadless fork and stem and it works perfectly.