I recently bought a 1991 Chevrolet 3500 reg cab dually with 5.7 350 V8 4x4 and a 9x7 contractor sides dump box. The truck only has 18,000 orig. miles. I planned to use it for spring and fall cleanups with a leaf box and towing a 20ft open trailer, landscaping and plowing in winter. My concern is how slow it is! I don't need something fast, but 0-60 empty not towing a thing is around 25 seconds, and towing about 3000-3500lbs is around 45-50 seconds. Is this normal for this engine and set up or is something really wrong? Any input would be greatly appreciated.