the vacumn advance goes down from carb to the dist. it should be a small hose smaller than fuel line. this is a rochester b right on a 65 chevy? if you have a hei dist you woun't have to worry about the dwell setting but you will if you still have points. have you checked how much vacumn you are pulling and set the timing with the vacumn gauge? might give it a try, might find out if it timing or vac leak or what. you can't always trust a new carb too. good luck. hr