The two big factors, engine operating range and displacement, are the same.
Can anyone offer the LDS max boost in psi?. The LDS-465-1Trouble Shooting Manual spec. is 18-20"Hg at 2400RPM(page 34).
The manual indicates induction air flow is rated at 550cfm (page 10). The LDT air filter element is labeled 440 cfm.
Since air flow is higher I have to assume boost is also higher. All thing being equal higher boost means higher turbine speeds. There is a point when the compressor efficiency drops off and/or the stress on the turbine/compressor wheels gets too high. Designers then change the nozzle area(A) or distance from center shaft to center area(R). This ratio (A/R) determines gas flow. Most turbo companies use that number to size turbine housings (20y ago Schwitzer used just the A to designate size).
It's likely the bigger turbo adds not only extra boost but extra air not intended for combustion, to cool the EGT, as Djfreema points out.
You probably should study manifold pressure and EGT after installation, adjust IP as needed. If you run high boost it might be prudent to check the head nuts for torque.
I'd guess if you set IP to run it like a LDT the boost may rise a bit slower. If you set the IP to run like an LDS you will put more stress on the engine. My LD seems to tolerate 12psi at 2500(13psi at 2600) all day long.
Waste gates are nice control devices. Designers often allow boost to rise at a faster rate with a waste gate.
I've seen the smaller non-waste gated turbo on the LDS. They may have been substituted in service because of parts availability issues or indifference.
JimK