If you want more TQ put the 5.8 in, there's nothing you can do to the 5.0 that will give it the 75-100ft/lbs advantage 50 cubic inches provides. If your truck is mass air then the biggest issue you will have is obtaining a flexplate to match the 5.8/4R70W combo. The 5.8 will drink more fuel around town though, that's just the way it is.