Granted the front carries the weight of the engine all the time, but the majority of these were farm work trucks, often overloaded and driven in the fields and on gravel/dirt roads. I had the good fortune of being able to talk with the original owner of my 54 3100 and he told me that quite often he would put a cow or two in the back to haul wherever, as well as loading it down with other things. I'm glad that you found that leaf springs aren't as frightening as you originally thought!
Samantha