If you Google how to get more out of a mechanical cummins you'll find results on a plate and adjustment procedures. More boost needs more fuel.Your going to want EGT sensor if you push it more.
I didn't see year or type of injector pump on your rig not sure if fuel plate star wheel adjustments work.
95 Monaco Crown Royale
M11 400hp, 4060 trans.
Aquahot, Generac Guardian7.5k