Vacuum Problem?

Now we are cooking
#1) the 4bbl carb needs a 4bbl bracket and a 4bbl cable. I bet you located the black part of the throttle cable into the clamp, instead of the long metal sheath termination?
#2) it would appear that the engine is pulling in air from somewhere its not supposed to, and the curb-idle screw was cranked in to compensate for a very low idlespeed
#3) I bet you havent hooked up the KD rod yet.

Okay. The first thing you need to do is unclamp that throttle cable.You are looking at the potential for a runaway engine. Then you need to answer the questions.Then we will dig into it.