Yes it should be bolted down ! They must have forgot that part of the install?
well the slot is used so it can travel without swinging around. the adjustment should come from the bracket. You can play with the kickdown adjustment. If its still the stock bracket on the new carb. Then you need an adjustable Throttle/Kickdown cable bracket.Since I got my car back from a professional manifold/carb install (Holley S/A) I've gotten the sense that the car is not automatically downshifting "as requested". Looked at the kickdown/detent cable at the carb and noticed that the nut/bolt used to adjust the cable is loose and not tightened down at a specific adjustment point.
Sounds stupid, but shouldn't this be tightened down somewhere along the slot and not allowed to run to the end of the slot before pulling?