confused here..  u wanting to  put the power unit  injection pump on the  dodge engine??    That power unit pump will be a governed pump.. and driving will be 'weird'.  

  Your 91  will be  rotary pumped,   and  quite possible  your  power unit will be inline Bosch.

Confused  because  you said  the dodge is junked out..but your title says the 5.9 is good . so are you  going to fix up the  truck? 

'splain  what is going where,  and for what  purpose!!