ok,i removed the carter 1 bbl from my 225/6.it only had two vac hookups the pcv and the vac advance.i put on a carter 1bbl that was on a two year newer car than mine for only six months.everything hooked up fine and car started up fine,but this carb has a third vac hookup that i plugged off.when trying to drive at a steady speed the car is now surging,never done it before..just hoping you guys could give me some ideas as to what might be wrong..new pump and filter was put on also and all connections are tight,even checked the ones at the tank...thanks in advance for your help

have you tried switching the vac hoses and checking the timing. do you have any pits of the carbs

i was looking in my chiltons book and it showed the third hookup running from the carb to the air cleaner..i have the smaller air cleaner with no vac line hookup..

the carb must be new than late 60`s, i think 73 on had the vac vavle on the breather some had it on the fire wall. some of the other on this site have better info on that, but the surging problem is it still there?

the surging is still there,it is like a bad miss i guess,but it didnt start until i put the new carb on

what was wrong with the old carb ?