Bentley L410 (6.75 V8)

Bentley and Rolls-Royce's 6.75-litre V8 — the L-series — in the Continental R, Arnage, Mulsanne and their Rolls-Royce equivalents.

⚑ It was in production for sixty years, from 1959 to 2020, which makes it the longest-lived V8 in this catalogue by a very wide margin. An engine that old carries every era of engineering at once: a 1950s pushrod architecture with, by the end, modern management and twin turbochargers bolted to it.

So the generation matters more here than on anything else. A carburetted 1970s L-series and a 2018 Mulsanne's share a bore centre and very little else — establish the year before applying anything.

Everything about it is specialist, and that is the practical point: parts, procedures and the people who know it are concentrated in a handful of places, and generic V8 experience does not substitute.