My 48 loadmaster has 8.25 20's and a 261 with 4 speed and 2speed rear end. It is wound pretty tight at 45. I usually drive at 42 miles per hour . I have driven it 100 miles in 90 degree weather with a heavy load up to our cabin and it ran just fine. I also have the big capacity radiator. It is amazing all the things you see along the highway at that speed. ;-]
