We happen to have two of these, one is our 4,000 gallon water truck (for construction sites) and the other is an M813 w/ the crane and winch for the sectional bridges which just sits. Also have an M139 parts truck.
Have driven the water truck around on the highway some, but with original old rubber (1961) we do not run it loaded. Clocked @ 62+ mph on a slight down hill grade once, but it still is not a real power house and if it has any load it really dogs down. With the 602 it also costs a small fortune to run any distance @ speed.
In most all of the states, you can't run a real bridge truck on the road w/o an over width permit w/ signage. On the water truck we singled out the rear ends which makes it just under the maximum width allowed. There are photos on this site somewhere I posted of this truck back a number of years ago.
Thanks