The way it is hooked up now is opposite of how it should work.
You need everything you pictured in your first post. Not just the slotted linkage. See the pin and adapter that bolts to the carb linkage that the throttle cable is attached to. Do yourself a favor and read through this thread. There are a lot of photos, information and part numbers of what you need. 2-Barrel to 4-Barrel Conversion