Here's the scenario...I have a 2002 Dodge 1500 quad cab with the 4.7 engine.I have been using Quaker State and Mobil 10w30 since it was new.I'll be doing a lot of towing this summer going to the drag strip(5000lb total load car and trailer)and am considering switching to Mobil Delvac 1300 15w40.Worthwhile or not?