Porsche 928 H50 Concept is the ghost of Panamera past

There are plenty of reasons to hang around Pebble Beach this time of year, including the fact that manufacturers love to use the Concours d'Elegance as an excuse to roll out some of the more inventive concepts of days gone by. This year, Porsche parked the evolutionary ancestor to the mighty Panamera at its display.

The 1987 concept is one of two the German automaker whipped up as test beds for the idea of a four-seat, four-door sports car. All told, the automaker clocked more than 5,000 miles on this particular creation before deciding the extended 928 architecture couldn't deliver the rigidity requirements necessary to wear the Porsche crest.

The H50 Concept delivered 330 horsepower from a V8 engine, which was enough to push this awkward-looking long-roof to a 168-mile-per-hour top speed. Certainly nothing to sneeze at in '87. Seeing the machine parked next to its eventual progeny made drawing parallels between the two all too easy, especially in the hindquarters. Check out the gallery to see what we mean.