I get 9 mpg towing and 11 when not. I only use the truck for camping or yard work so the mpg isn't an issue. It has a new HD suspension and is in great shape.
http://67-72chevytrucks.com/vboard/s....php?p=6305428
As far as getting a new truck, I have had this one since 97 and it has done all I ever wanted. Since getting the camper 2 years ago I am seeing that it would make more sense to get a 10-15k quad cab truck that is newer and can haul the whole family. The alternative is spending a couple grand to install a 454.
I read up on the 8.1 and newer trans but can't get my arms around the 4-5 grand it would take to do it. The 454 would be cheaper and have similar mpg and the power needed.