This Jaguar 3.8-liter inline-six engine, originally from a Jaguar MK X, underwent a comprehensive rebuild including cylinder head repair, replacement cylinder sleeves, and new bearings, guides, valves, and valve springs. It features triple SU carburetors, polished valve covers, and a 1961 casting date, with the engine number ZA1331-9 indicating a 9.0:1 compression ratio.