My 5.7 liter silverado is now on 130,000 miles. The last couple of thousand miles I have been using Motorcraft 10w-40 UOA -yet to be done. When I changed to the heavier weight oil the assumption was it would help prevent wear-but after reading some of Bob's studies that is very debatable. After the motorcraft change I would like to go to Schaeffers oil. Patman has a good point that the pushrod GM v-8's like a heavier vis. 30 weight oil. Which Schaeffer oil would work best? I would want to go with one that would have a nice pour point as it does go below zero in West Virginia in winter. I am interested in Schaeffers because of the nice additive package and the ability to hold viscosity. Seems like other oils have the thining issue except for the cream synthetics like Mobil, amsoil,and Redline. I want this truck to reach 200,000 and beyond and to help that Schaeffers seems to be a good choice. Any help would be appreciated. This board is very interesting- with a bunch of knowledgeable souls.