15W40 Motor oil with over 1600ppm ZDDP in high grade mineral oil. Specially formulated for flat bottom lifter engines. Contains the correct levels of deterents,and dispersences to prevent deposit formation of sludge from contaminates, primary and secondary ZDDP, polymers that have both shear stability and thickening efficiency capability to protect bearings. Has an additive that helps the oil cling to the moving parts to prevent hard start