Porsche 904 Carrera GTS

Start with identity, paperwork and originality. The strongest cars carry a continuous Porsche or recognised-specialist service file, matching numbers, both keys, complete books and tools and — where available — the Porsche Certificate of Authenticity and factory build documentation. For the 904, chassis-by-chassis history is the most important variable — continuous documented ownership, period competition history where present, and factory or long-standing marque-authority verification of the fibreglass body and steel ladder chassis.

Inspection should be led by a Porsche 356/early-motorsport specialist familiar with the Type 587/3 four-cam engine, the ladder chassis and the fibreglass body-to-chassis bond. A proper pre-purchase inspection includes cold-start behaviour, an undertray-off inspection of the engine and gearbox, chassis and suspension survey, brake condition and a long enough road test to expose heat- and load-related faults. Deferred maintenance on a specialist Porsche is almost always more expensive than buying a better-sorted example.

Use a paint-depth gauge and a lift inspection. Confirm any PPF history; inspect splitters, sills and undertrays for evidence of contact; and price concealed accident or corrosion damage severely. Rust in wheel arches, sills, floors and battery-tray areas is the primary body concern on the earlier cars.

Specification, colour and factory options move values meaningfully. Buy the best-documented example in the most desirable specification you can justify rather than a tired car of a rarer derivative that will need years of corrective work.