You may want to look at that carburetor also. Re-adjust fuel mixture screws. It may be running too rich. Also the rod in the acc. pump should be in the middle hole for the AVS's. Anyone agree? You say it is a carb. from the smog era! Does that mean it is jetted on the lean side? Get timing fixed first then work on carburetion! The engine running smoother after you take the air cleaner off means that you are getting more air thru the carb. and it is leaning out the carburetor which sounds to me like it may be running too rich at idle!