For 31 years I've had very quite engines on M1 oils, with the exception of two Ford diesel engines I had in the 80s. A friend with a 300 ci Ford truck, on dino, always had noisey lifters. After switching to M1 10-30 his engine quited right down. Also the machine shop where I worked for many years had most of the employees using M1 oils, my doins, in a variety of engines. All said their engines were quiet on M1 oils. Some ran well into the 200,000 mile + range.