I just finished up this build. I put a Demon 625 double pumper I had from another build (gm). The trouble was the throttle linkage on the carb pulled AWAY from the trans kickdown. This car at some point in the past had a slant six with column shift that had modified intake brackets to adapt existing linkage to the V8. The rest is one looong kickdown rod to the kickdown lever on the trans. We made up a new " flat blade slotted bracket " to attach to the TOP of the carb linkage travel to PUSH the kickdown rod to activate the kickdown. In the garage with engine off with the gas pedal mashed, my helper observed the kickdown rod pushing the trans lever all the way back ( but not into a bind ). Yet with Pro complete rebuild with shift kit and stall (2500) with 3:91's I too am not achiving a " kick down " on the street. I am investigating this later today. There is a youtuber 318willrun that had some good footage about this.
