I used to maintain a fleet of trucks that they converted to propane in spite of my advise not too. These college grads sitting in there plush offices know more then a dumb mechanic. The systems were unreliable. We had a lot of valve jobs from valve seat recession. They were clumsy to fuel & with the short range they had to be towed back to the warehouse to fill up. A dual system would solve that problem but then it is more complex.
