First order a 1964-8 Corvette chrome shift knob or a 1969-81 black chrome shift knob from Ecklers, Zio Products, etc for under $20. They are 1 3/4" round, heavy steel, top quality shift knobs. When it arrives, pry off the shift pattern cap on the Z06 shifter. You will see a T-shaped pin. This can be removed by prying up with two screwdrivers or by locking a pair of vice-grips on it and pulling up with a LOT of force. You can then unscrew the old knob and replace with the new one. The threads are exactly the same.
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2001 Torch Red Z06
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2001 Torch Red Z06