The prechambers were redesigned and the pistons matched to them sometime around when your engine was built. I presume you have the prechambers with the flat bottom and a sharp edge around it below the fireholes. The later prechamber is rounded with no distinct edge. The holes in the pistons match the profile of the chamber.

I think you could match the chambers to the piston. And, as Peter said, you need to set the protrusion depth. You also need to be sure that the pistons are not too high out of the block.

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician