X,
The question is, does your engine have enough exhaust energy to drive that turbo? There are a few ways to determine this. You could contact Holset and just ask them. Ask them what flow rate you need, or if you can talk to an engineer ask how much enthalpy the turbine needs to make maximum boost. Or call Cummins and ask their opinion.
Another way would be to check the weight difference of the shaft and turbine/compressor assembly against the HY-35 that's in your truck now. If there's not too much difference, you might get away with it.
What about overall size? Are these turbo's similar enough that a new exhaust flange could be machined without too much work?