To quote from page 6.28 of the factory service manual, "MAIN BEARING SHELL SELECTION AND JOURNAL CLEARANCE CHECK".
The crankshaft has automotive type shell bearings at the rod and main bearings. The other lowerend rotating stuff such as the balance shafts are all on ball, roller bearings or removable bushings.
The camshafts don't have bearings, which seems less that desirable to me. But, if it came down to desparation, there are ways to save the head if the cam bearings became too loose.
