By comparison to many mass produced engines the K series is very precisely engineered. One example of this is with respect to bearings. In order to correct for variations in production there are three thicknesses of main bearing available, which are colour coded on the edge of the bearing.

Green main bearings are the thinnest
Blue main bearings are intermediate
Red main bearings are the thickest

To establish which thickness of bearings are needed in each position there are two sets of information on the engine.

At the front of the engine, on the exhaust side of the main bearing ladder (between the crank pulley and the oil filter fitting) are a series of five letters.

These letters will be upside down.

The first letter (stamped closest to the sump) corresponds to number one main bearing.

On the front web of the crankshaft are a series of five numbers.

The first number (stamped closest to the centre line of the crank) refers to number one main bearing.

Cross referencing the letters stamped on the bearing ladder with the numbers stamped on the crank gives the grade of bearing required.

Where two colours are listed the thicker bearing should be fitted in the bearing ladder.

An engine set of main bearings includes 7 plain bearings and 3 grooved bearings.

All of the bearings in the bearing ladder are plain bearings.
The outer bearings (1 and 5) in the block are plain bearings.
The centre bearings (2, 3 and 4) in the block are grooved.