Emissions Stuff
OP, if you don't have one, you need to scare up a service manual. The emissions are a combo of the fuel / carb section and the emissions section in the back. These systems changed in some way almost yearly from 68--76. Unfortunately, I don't believe MyMopar has one for 74, you will likely have to buy it.
But there IS a 73 manual, it might be it's close enough to get you going.
Another link:
Free service manuals