Bought the K1500 about 6 years ago to tow travel trailers. 3.73, 350, 4L60e. Had 120,000 on it, one owner, always garaged, constant oil changes, motor had original plugs and wires. Tuned it up, new plugs etc. Bought a 28 ft Trail Cruiser a light weight trailer, 5,000 lbs dry. Probably 5500...