Porsche Eyes 4.0L Flat Six With 9,500 RPM Redline

Porsche is hopeful that its naturally aspirated 4.0-liter flat-six engine will live on and is even investigating an evolved version with a sky-high redline of 9,500 RPM.   Speaking to Australian publication Which Car, Porsche’s head of GT road car engines, Thomas Mader, said he does not think the 991.2 GT3…