[Navy Lifer]

Mike,

Since the GS brakes will require an 18" wheel, minimum, the next question is why not go with a 4.75 stud pattern all the way from the hub in front? It would save the machine work on the rotors, so you could use either the KORE3 hub and specify the smaller pattern and whatever hub pilot diameter you want OR create a hub using 88-92 1LE Camaro rotors, since you'll be using an adapter of some sort anyway (high offset wheels). The rear is probably simpler to stay with 5x5 and with the really deep adapter, the larger pattern is preferred, IMO, even though you're converting it down to 4.75 for mounting the wheels. You can cut a step on the back of the 1LE rotor for the tone ring to mount as on the stock hub.

You should contact Jason Hurst (don't remember his screen name) or JaySS if you haven't already, regarding front hub options other than KORE3. Todd (TCE) will also supply just his hubs, I think.

I will say that the KORE3 hub, being "turnkey", is still worthy of consideration--even at it's current price. With the C6 rotors, you end up turning down the OD of the hub so much that I am not that crazy about using them as 5x5 when 4.75 is an option--gives you more margin to the hub OD to ensure there are no cracking or breakout issues if the casting has any voids in the are between the stud hole and OD.

A few threads and posts you may have seen.....

http://www.impalassforum.com/vBulletin/showthread.php?t=232588

http://www.impalassforum.com/vBulletin/showpost.php?p=2196406&postcount=5

http://www.impalassforum.com/vBulletin/showpost.php?p=2216378&postcount=17

http://www.impalassforum.com/vBulletin/showpost.php?p=2414180&postcount=43

By the way, what is the rotor source--if you don't mind?

 

[Navy Lifer]

The C5/C6 rear rotors are cut to mate/fit the 4.75 axle flange. The B-body 5x5 flange is larger in diameter--don't know the difference, but Dave looks to have used 6.625".

Thumbnails show:

1. a DBA 12" C5 rear rotor, which has a completely flat inside surface, no machining was required to clear the larger 5x5 axle flange

2. an OE Z51 C6 rear rotor, before machining out the step to clear the larger flange and fit flush to the flange surface

 

[Navy Lifer]

Make sure the center bore is chamfered on the inside to clear the radius on the axle pilot.

Really curious what the source/country of origin of your rotors may be--do they show signs of balancing (edge milling)?

....he didn't know if I could use his hubs, due to having the Z06 wheels that the spacer may not be able to be hubcentric, or wheel centric rather.

Not sure I understand--how thick are the front adapters?

 

[Navy Lifer]

Funny thing, looking at Tobin's (Kore3) fitment templates, this setup is shorter in overall radius than the C5 hybrid setup (C5 PBR Calipers, 355mm rotor) by .41 inches (8.33" C5 Hybrid vs. 7.92" C6 Z06 Setup).

The C5/C6 PBR twin-piston floating calipers do typically have a higher "bridge" height--ie. radius--compared to a fixed-piston caliper. That is why a Wilwood or Movit front brake kit with a 13.5" or 342mm rotor can fit inside the OE Impala SS wheel, which isn't possible with the floating C5/C6 calipers--limited to the 325mm rotor.

The floating caliper requires more material in the bridge area to provide enough strength/stiffness to keep the pads parallel--which the design of fixed-piston calipers deals with in a different way, with a much lower bridge height.