904 tranny issues

i recently put a new edelbrock carb on my car and before going from 2nd to 3rd had a minor hit going in not it really hits shifting in that gear, is the kickdown arm not set right, or is a vacuum line needed if so where does that hook to?? im lost just bought this car a few weeks ago suppose to be a rebuilt tranny in it.. maybe that was a original lie? can anybody help me.