I agree, I would want to see a spec sheet to make sure. The bottom ends (other then crank, piston, rods) is supposed to be the same, but no guarantee that it was machined the same way. A number of motors that use the 'same' bottom end have parts that have to be machined out to allow the necessary clearances for a longer stroke in larger displacement versions of the motor. It is likely that it would work, but I would certainly not guarantee it...and you would be looking at spends whatever money and time just to end up not having a working setup (at least without machining if it doesn't work).
Also you would probably want the 2.3jdm ECU as well...which might necessitate a wiring harness change as well. I mention this because the differences between the USDM 2.3 and JDM 2.3 are likely code changes in the ECU on top of a difference in pistons (JDM has a higher CR then the USDM 2.3 as far as I can remember).
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