[Super73]

Well I have 2 vehicles with late model motors. I did not add to the poll but could if you want.

Wife drives a 2007 Trailblazer SS AWD. It has an LS2 in it. Prior to installing an Electric fan, it was getting an average of 14.4-14.7mpg and the best long trip drive was 15.5mpg. After the fan swap and some shift point settings/converter lock up adjustments, it averages 15.5-16.0mpg and has knocked down the same long trip mentioned above at 18.6mpg. Here TBSS weighs 4,900lbs with out driver and a half tank of gas.

My 63 with the 347/4L80E, big cam, 4,500 rpm verter, 4.56's and 30" tire was getting 12.5-13mpg on the freeway. Truck at it's lightest weighed in at 3,525 but I didn't really notice a mileage change from the 3,900 lbs it once was. I'm not too sure with the new 418/powerglide combo.