It's possible that the fuel pump was not installed properly also. It is possible to install the fuel pump and not have the cam hit it like it should.
One example is the pump in the link:
http://shop.advanceautoparts.com/we...Airtex_5406595-P_52_R|GRPFUE2AMS_490553401___
This pump will fit the 7.3 diesel but as you can see with the long arm it has it is possible to install it above the cam.
When Mark and I replaced my pump we pulled out one with a short arm and the one he brought home with him after work had a long arm. It was not until the next day that we realized that both the short arm and long arm would work however I went back the next day with the long arm one and replaced it with the short arm one which probably worked out for the best anyway because I do not think we would have been able to use the long arm one in a van as their is not much clearance.
According to the directions your supposed to bump the motor until the cam is up top so that there is no downward pressure on the arm when installing but even looking with a light and a mirror being that everything is tight in a van you can't see the cam. Fortunately when I did shut down the motor before we pulled the pump the cam was in the right position.
Also if you decide to go electric in the future a small block Chevy fuel pump block off plate will work blocking the fuel pump hole.
If mine ever goes again I am going electric because if you run out of fuel you do not have to crank and crank and crank. At that point all you would have to do is turn the ignition on and hold the schrader valve open until you get fuel coming out.