i have a 56 fairlane 292 fordomatic,all stock with a holley 570 cfm carb and electronic ignition,timing is set at 6 degrees btdc,vacuum at 17".my problem is at cruise,vehicle surges severely,commonly refered to as trailer hitching,also right off idle when taking off it will lay down,but if you get into it a little more it goes pretty well.it just seems to me that the problem is still in the carb.i haven't broke into the carb yet but was wondering if jet size may be the culprit