sorry for the late replyI may be able to help you some. CPL 0858 was a very common one used in road vehicles. There were different specs on certain parts depending on application. One version came on the Ford E350 vans. Generally, you will see it with a top mounted turbo and a belt driven vacuum pump. It would have a transmission adapter with a small block Ford bolt pattern and a flywheel for a manual transmission. The GM units came in 2 designed. Both those version will usually have the turbo mounted in a low rear position. That turbo tend to have a different sized turbine housing. Normally, no vacuum pump on those. The transmission adapter is a standard GM on both versions. The difference is one come with parts for the TH475 that was found in GM P30 van. Maybe 10% of the vans had a manual transmission and those have a GM flywheel. Have you got a photo of your engine? If you can tell me which engine style you have I have ESN's for them. If the data plate is missing from the front gear housing, the engine serial number (ESN) is sometimes stamped on the rear of the block just below the head. This happens only when Cummins has rebuilt the engine. You mention the CPL and the injection pump can give a clue to that number. CPL 0858 changed injection pumps a lot over the years when it was produced. There were about 8 or 10 different numbers for that CPL.
Yes it would be a gm one I believe but it did not have the trans adaptor or flywheel but the turbo was lower mounted and it does not have a vacuum pump. sadly no stamp on the back of head
I'm in the process of buying main bearing but idk which ones I should get. it seems to be based on serial numbers.