I think when spring rolls around I am going to try 15W40 in my Olds 307 wagon and my Chev 305 truck. I was out at a few parts stores today and I was looking at the 15W40's that were sold. I can easily get the following oils locally: Mobil Delvac 15W40, Pennzoil Long Life 15W40 and Shell 15W40. I can also get Esso, Havoline, and Petro Canada oils, but I am not sure if they are available in 15W40. What would be the best choice among these and why? I looked at the VOA reports on the Pennzoil and Delvac in the archives. I am still new to oils, so I am not sure which one is better. I did note that the Pennzoil has more moly, but the Delvac has more magnesium. These vehicles are used for mostly moderate trips, but the occasional short trip, and at least one good long trip a month. The car is not driven in winter, and I will run a lighter oil in the truck for winter months. I am looking for an oil that will provide the best protection, not maximum drain intervals. I am also hoping that the extra detergents in the oil will help clean up these higher mileage engines.