there sure is a governor on it. its inside the fuel pump.
you could google "3k governor springs" or turning up a first gen 5.9.
here is a good link to start you on the way to turning up the diesel.
Beginners Thread - Read First! - Dodge Cummins Diesel Forum
i think the first gen have a fuel pin you can rotate for more power.
the best way to go faster is to regear the rear differential. that pumpkin is what slows us down, not the driveline.
raising the rpms will get you more speed at the the expense of the the engine.
$ for $ i would put money into a 4.3 or 4.1 rear.
i didnt, i think that way would have been cheaper.