Piston Selection
The pistons are select fit to each bore. There are three different grades of pistons available; A, B, and C. The piston identification (2) is located in the middle of the block on the right side of the engine. The bore identification starts at the top and reads downward. Bore #1 is at the top and bore #4 is at the bottom.
The piston, rings and rod are serviced as an assembly, after determining what size piston is needed, to determine correct rod bearing size. Refer to Engine/Engine Block/BEARING(S), Connecting Rod - Standard Procedure .