The new rotors are not going to be zero since they were not machined as a unit with the hubs and spindles. Not to worry, most people replacing vette rotors for the past 40 years never even knew about runout let alone how to check and correct it.
As Hib mentioned, be sure the bearings are correctly adjusted. I have my own method which is pretty much like you can find anywhere.
Then be sure there are no burrs on the hubs or spindles. I tap the hubs and spindles so I can bolt the rotors on, I like it a lot better then lug nuts or rivets. You can use lug nuts though. Use all 5 when you do.
Be sure your indicator is rock solid,there can be no movement in it otherwise you're going to waste your time.
Slowly rotate the rotor when checking. Do not jerk it around or you'll get a false reading.
When you know the true runout you can either shim or turn them.
The fronts can be turned on a brake lathe if the rotor is bolted on tight and the operator only removes a few thousands. The lathe will pickup the races and run true. The rears are different, an on the car lathe is one way, removing and machining the spindle/rotor assembly is another, I shim them and get them to under 002" bolted on,without removing material. I've done a LOT of them like this over the years and that's what works best for me. I make up my own shims from SS shim stock. About $80 for shims and $80 for a punch set from MSC. If you're only doing a set of rotors check your hardware store for shim stock. You want 002,004,006,etc increments. Mostly 002 -006 sizes should work. You can find my whole thread on this on digitalcorvettes as well. It has a lot of pictures.
