I just bought a 97 Yukon with a 6.5, so far so good. I'm getting about 11L/100KM 40% city/60% highway driving running 3.73's. I am sure I can improve that if I keep it. I have been running 6.2s for the past 20 years and they have both been good to me. I am restoring my 91 with 750kms on it, I...