3.08 were the gears gmc put in their trucks with a 3 speed. I had a 270 GMC 6 cylinder 3 speed with that ratio. The 270 did fine around the city, and I'm in San Francisco, a city not known to be flat. It did not do so well towing in the city. Didn't have the gears to really get started. Freeway speeds of 70- 80 mph were not a problem for my truck.