You have not stated what model of turbo you will be using. But if you look at Cummins' compressor maps you'll see only the HE500 series (HE551V, HE551Ve, HE561Ve) are capable of 55psi boost (4.76 pressure ratio at sea level) in your engine's flow range. Given the 16L engine it came off of, its a good bet its an HE500.
If you look at the map (attached picture) you'll see the flow range its capable of pushing 55psi is VERY small, between 0.38-0.5kg/s. That means that ANYTHING outside of that flow range at that pressure ratio will either be in surge or overspeed.
Use this to help understand how engine and turbo flow works, its already setup for a Mack E9: Not2Fast: Turbo Calculator
Here is a calculator to convert LB/min to KG/s: Mass Flow Conversion
You will see that with half the engine flow, 1500-2000rpm is right in the flow range for 55psi with an HE500. However from idle-1400rpm trying to make 55psi will cause the turbos to surge.
I'm not a "knowitall", but I do know turbo and engines.