Always used the Mosier axles, and I am still 4 lug with 5/8 studs. If your truck is anything like cars with slicks, the bigger tires will most likely slow it down. I have seen alot of cars running big tires like Kenny's Chevy II, speed up by going to 28x10.5's, I guess due to less rolling mass and friction. But you have nothing to loose by trying, it all an experiment..
__________________
When the people fear the government, there is tyranny. When the government fears the people, there is liberty.
Thomas Jefferson