Good question that I don't have an answer for. I have a Roush black pool ball knob, it is lower and more comfortable than stock. However the big ugly silver nut that it tightens against shows since the boot does not slip over it.
I've heard of people winding a rubber band on the shift handle (under the boot) at the heighth you want the boot to stand. If a rubber band doesn't work you could probably find some rubber grommets at a hardware store that would do the same thing.
current eBay item number 360162874875 from seller zrchris 2005-09 Mustang Shifter Shift Knob Boot Retainer Sleeve SHIFT KNOB NOT INCLUDED! THIS AUCTION IS FOR THE BOOT RETAINER ONLY, which is a necessary item for anyone looking to put a classic Hurst knob on a new Mustang. The stock knob has a ring at the bottom to hold the boot, but aftermarket knobs do not, and so you need this piece to make everything fit Brand new custom boot retainer with M12 x 1.25 thread for manual transmission Mustang from 2005-2009 with stock shifter or aftermarket shifter with stock threads. Not all aftermarket shifters have stock threads; the buyer must determine compatibility. Fits 5 or 6 speed, all models, even GT500, but not Shelby GT with Hurst shifter or Bullitt Mustang due to the smaller boot. This retainer is custom machined, carefully designed to properly fit with the stock shifter and boot. This is an exclusive "zrchris" item, designed, produced, and copyrighted by this seller.
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