1985 Chevrolet Silverado Does 350 Engine Runs Rough Smokes Blue White Smoke

the smoke is probably due to bad oil seals, they didn'thave much of a seal as it was an o ring, there are better ones available called positive seals. they cna be changed without removing the cylinderhead if you have air pressure available and a valve spring compressor for on the car. most mechanic shops can do it. they weren't the best champs for mileage either. have it checked by a pro for maybe time for a carb overhaul or if a tbi unit check for a blown gasket beneathe the unit, spray carb cleaner at base front and back if rpm changes it's leaking vacuum