Porsche is rumored to be powering the new 988 with a 4.0L flat-eight engine. Porsche engineers were quoted saying 4.2 liters is the upper limit of flat-six motors because the weight of some internals gets to be too much. The rumor also states the new engine is being tested with four turbos producing over 600 bhp. I don’t know where the rumors come from but I sure hope this one is correct. The last flat-eight was in the Porsche 908 race car.