I have to apologise to all those taking part in this thread - yesterday was my birthday and my daughter had bought me a rather fine single-malt Irish whiskey, which got the better of me late in the evening, The photo I have depicted is indeed Gustav Schlup in his Elva Mk VII powered by an Alfa Romeo engine, but of course the year is 1966. The puzzle car dates from 1967, and in that year Herr Schlup campaigned an Elva Mk VII powered by a 2.0 litre Porsche flat 6 engine. I cannot imagine he bought another chassis, and assume therefore that he re-engined his '66 car.
Now here's the interesting thing - the "certain site" which contains many sports racing car records, confirms the number of that Elva at the Norisring as #26. I have also found the exact same photo as SACO, on a German-language site. It makes me wonder whether Schlup re-bodied the car at the same time as he re-engined it.
The Gachnang brothers had a strange way of making racing cars - they invariably assembled something from what they had lying around, and often used obsolete cars with a modernised body. The Ferrari-engined sports car I'm pretty sure used the motor from their old re-bodied Ferrari 250TR, stuck into an old Cooper Monaco frame. The Cegga-Maserati claim for the puzzle car quite rightly confused puzzler D-Type - that car started life as a 1.5-litre Formula 1 car, then was re-engined, still in single-seater form, with a 2.0-litre Maserati engine for European Hillclimb Championship events. Later still, it was re-engineered as a Group 6 racer, with a body on the lines of a Mclaren M6/8, and still exists to this day in that form.
I can't prove anything, but I'm sure in my mind that the puzzle photo was incorrectly captioned by the magazine. That is not a Cegga, but Herr Schlup's Elva-Porsche MkVII from 1967 and 1968. From 1969 he raced a Porsche 911.
I've just found a reference to this car on a French site - it is mentioned in Janos Wimpffen's book on Elva cars as an Elva MkVII converted by Schlup to run a Porsche 906 engine - the windscreen apparently comes from a 906, and it certainly looks the same.