I purchased new slotted rotors from Vette Brake Products and I'm having trouble with rotor run out on the front. It's about 10 thousandths of an inch. I checked the hub before the rotor was slid on and its .004". Any ideas about how to get to .002 or less. Thanks

Sometimes you can re-clock the rotor on the hub, and find a place where the run out cancels each other.  If not, the "correct" way is to take the hub off, and have everything trued on a lathe, then riveted.

Larry

Yep...sometimes you can simply install the rotor in a different orientation on the hub, and lessen the run-out. You have 5 different ways to try! Make SURE the hub is completely clean of any rust, or anything else that could keep the rotor from seating properly...just a wee bit of dirt can do it. Also, when checking the run-out, make sure the rotor is properly fastened to the hub with ALL of the lug nuts.
You can also use thin brass shim material to make shims, if needed, as a last resort, if you don't want to, or can't have the assembly trued on a lathe.

Is it only one rotor on the front or both? You could try swapping rotors.

These rotors are slotted an can not me turned. They are also directional and can't be switch left to right. Only one of the rotors is out of spec. Has anyone had any experience with turning just the hub.

With some of the new cars the runout is so picky that the mfgs make a shim kit.  The shims are slightly tapered and fit between the hub and rotor to correct the runout.  Im not sure if one of the sets will fit a C3 bolt pattern. 

Hey guys,

I picked up some tapered shim material (.002-.001) from NAPA.    I placed shims behind 3 studs and got the run out to within .001.  I was amazed at how well it worked.  The brakes are back on and everything seems to be working. 

Kewl! Make sure the wheel lugs are tight. You'll want to check them again after driving a few miles, just to be sure.
Glad ya got it done!