Gas Tank Deffinetly not! Carb,nah.. has been off the car and wrapped in plastic and is brand new although the secondary does not seam to open while car is moving, sounds crazy mean in neutral. Timing maybe! To what degree should i set to? Hey what about some kind of Points or Coil problem? Maybe its time for HEI. driveshaft im not sure about , wouldnt it only vibrate at high speeds? this seems to run rough in every gear towards the latter part of duration, although, I do have a high speed vibration in the shifter at around 60mph i really dont think its related but ive been known to be wrong, this does seam to be driveshaft, would drive shaft also cause poor performance thru lower gears? I wouldnt think so, What do I know though I sell carpet for a living,lol. Who said Vacume leak? Im thinking Vacume also. Where do i start with that one?