The 350 motor in my 1987 GMC pickup has well over 200,000 miles on it. When I first bought the truck about 4 years ago, it had that typical GM small block V8 habit of puffing out that blue oil smoke in the morning and using about a qt. of oil every 2 weeks. I started adding a qt. of the lucas heavy duty oil stabilizer at every oil change and that "cronic" morning blue smoke quit in 3 weeks!! My oil consumption weny WAY DOWN! My oil pressure went UP! I won't run my truck without it! IT WORKS! Thanks alot! Rich Johnson