This latest engine that I purchased has a boost gage port from Cummins which is an intake bolt that has a hole through it and a larger hex on top with the 1/8 npt thread in it. Never heard of this in the threads and though it might be good information. I don't have a part number, but the Cummins employee that I purchased the engine from said it was a Cummins part.

 

Check with Piers he sells them.

--Justin