Tag Archives: 15W-50

Should I Run Multi-Weight or Straight-Weight Oil in my Muscle Car? Ed Newman (Edited by Ches Cain)|Jan 12, 2016 4:30 PM   Much of the stigma related to this has been eliminated due to technology. Here’s the straight story on viscosity grade. The “W” number in, for example, a 15W-50 motor oil outlines the viscosity […]