I also just realized why the message from trigger wheels didn't make sense. The tacho driver is an actual product that they sell but isn't included in the kit and I didn't know I needed one. Son of a bitch.
I have a 1994 RRC with a 4.2 and non serpentine belts. I see individual parts listed but not a kit for the 4.2 non serp. Do I use the 3.9 kit or have to cobble together something from individual parts?