Don't forget the lead foot factor in MPG. It takes very little to keep ole Betsy moving down the road. That big engine purrs right along. But getting her up to speed in a different matter especially if you like to do it in a hurry! This difference is gas mileage is really quite remarkable. But who cares!!! I heard once that is takes less than 20hp to keep a ferrari going down the track at 100mph... once it reaches 100mph. That might be an old wives tale but I think the point is made just the same!