Geometrical accuracy affected the whole engine design in an effort to maintain the cylinder bore shape when assembled. The more perfect the cylinder bore, the less oil consumption and oil burnt in the engine is recorded as hydrocarbons at the exhaust, so bore stability was critical to meeting emission regulations.
The extended head bolts brought their own problems. Long bolts expend more when hot; slightly releasing the components they’re holding. So the bolts were routed through the block close to oil ways, rather than coolant passages. Oil temperature, so the bolts tend to expand with the engine as warms up, retaining tightness.
The cylinder bores were further refined in the machining process. After initial machining at the foundry, Land Rover diamond reamed the bores for maximum geometric accuracy. That meant the final, and less controlled, honing process could be substantially reduced.
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