Running on 4 cylinders

needs more fuel on the idle circuit 1/6 farest from carb could have a vacuum leak .idle circuit clogged up ,try gapping those plugs at .050 wide and check for a change, also some used a hotter plug in those cylinders because of a lean problem I thing ny16 was the plug ,But this is where SLANT 6 DAN can help you if he's out there