Chainsaw Repair

I was looking at the part numbers for the 3450/3750 and they do not share the same number for the 3000
So I would say the crankcases are different.   How they are different I do not know.

Muffler is smaller on 2800-3300 crankcase is wider on starter side front.  3450-3750, etc muffler is wider than 2800-3300.  Crankcase muffler opening is (starter side front) wider for larger muffler.  Clutch side of crankcase appears to be the same on all models. Starter side is diff. on 2800-3300 than 3450-3750,etc.
Shep