I have an 88 GMC P/U with a 5.7 litre 350 with 130,000 miles. It burns about a quart every 800 miles. I only drive the truck about 3,000 miles a year to pick up stuff at the lumber yard and things like that locally, so it isn't like I need to spend the money to replace or rebuild the engine under the circumstances I drive the truck. I would like to stop the smoking it does at idle and slow it slow the oil consumption of I could. I have always put in NAPA oil of the viscosity the engine calls for on the filler cap. I do not remember if it is 5W/30, or 10W/30. Any recommendation on another brand of oil/viscosity that might help this condition?