we have a westerbeke 8BD genset that has a mitsubishi block. It would seem hard for westerbeke to modify the injectors so it would seem easy to contact a mitsubishi dealer and provide the original injectors and ask for replacements
. there should be markings on the block itself (part of the casting) that would help identify the specific block. But it also seems from your post that all you may need is servicing and a good injector shop should have a database of injectors and be able to find the correct pressure from the id marks.
let us know what you find - finding reasonably priced parts
is not easy...