tired of buying pills so after a bit of research I made this. I used a propane torch to melt the plastic and solder off the pill studs. then soldered them to a potentiometer ( ? ) I had. I checked the resistance on this chart
http://www.sstang.com/techfiles/pill_rework.pdf
and my range was from about 1000 rpm to 6900 rpm. perfect! plug the pins into the pill holes and you're done. I'll come up with a better mounting solution but for now, it works! I might run the wires into the cabin so I could adjust the rev limit from the seat but don't see much need for it. I might do it as an anti-theft. with the dial turned all the way back it rev limits to about 1100 rpm. should annoy a car thief.