Matching-numbers Type 616/36 engine and correct four-cylinder engine bay
The single most important structural check on any 912 is whether it retains its original, matching-numbers Type 616/36 (or US-market 616/39) 1.6-litre pushrod flat-four in the correct four-cylinder engine bay. Long histories of 911 six-cylinder swaps, VW Type 4 conversions, and modern 1.7 / 1.75 / 1.8 / 2.1-litre big-bore rebuilds are well-documented in the market — many are excellent driver cars, but a numbers-matching 912 with the correct engine, correct carburettors (Solex 40 PI), correct sheet-metal shrouding and correct ancillaries is materially rarer and prices at a distinct premium against an engine-swapped or big-bore car. Cross-check the engine number against the Porsche Kardex / Certificate of Authenticity.

