For those using or thinking of using GM Metric calipers. Wilwood D154 Twin piston caliper has same mounting as stock. Available for 1" thick stock GM rotor or for .81" and 1.25" thick hat mount rotor. Also available in black. A little spendy at $ 180 each.
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Yes that is the new caliper. There is also other new ones that fit the early Vettes. and the rear caliper with hand brake cable.
I can beat those prices since I am a Wilwood dealer and they are located 3 miles from me.