T-56 shifter knob

Hello,
Does anyone know of a shifter knob that fits a stock t-56 shifter (16mm x 1.5 threads) with a button? I need the button for the reverse solenoid problem.
A parts store wants to sell me a standard B & M T-Handle shifter with a button and have me tap the hole to the right size. Has anyone ever done this? Problem with this is I can't find the right tap. If someone has done this before, where can I buy the correct tap and drill bit? I am looking for an easier solution.

Is the Pro 5.0 shifter the 16 mm thread? I am not opposed to putting a new shifter in the car.
Thanks
Rick

68 Camaro, t-56, 427

I drove mine for a while just muscleing it into reverse.. then I decided to just remove the solenoid from the side of the trans, and plug the hole with a freeze plug. Works fine, and gave me a little more room in the trans tunnel..
Another option I considered was mounting a large momentary pushbutton on the floor next to the dimmer, but it isn't needed now

------------------
Texlurch - 68 Camaro (Just a little ol' LT1 with a Hot Cam, I SWEAR ;)
" a little spray never hurt anyone, spank you very much!"
or the old standby:"I came here to race, not sell real estate. You ain't scared, is ya?"