ESC to non ESC help

[mhorning]

Well I finally bought an edelbrock 1904 carb and I'm about to change out my quadrajet. I was reading the directions on the 73-87 site and I see that it says that there are four wires on the ignition module. I looked at my truck (86 k10) and see that my distributor has only three wires going into the module. Now when I bought the truck someone replaced the engine, do you guys think that they may have also replaced the distributor? Or does the 86 k10 only have three wires? If so what should I cut to make the conversion?

Mike