I used th eHurst switch on my 69z28.Follow th link that CarlC posted, with there adivce I got it working for around 22$. I was missinng the factory backup light switch on the column, so I don't know if you'll need to remove it. All I did was disconnect the wires from it, and hook them up to the hurst switch via a homemade harness that goes thru the fireawall. You may have to play with the adjustment on the switch. Once I got it working correctly it has worked perfectly ever since.