GM at one stage went BROKE and was bailed out by the US Government. The GM 2 stroke diesels would never meet the later pollution standards. GM was steadfastly anti electric, ALWAYS. The BEST Piston engine for specific fuel consumption/ HP Hour was a Wright RADIAL with 3 Power recovery Turbines. Radials are NOT more thirsty than any other configuration for their HP Output . There are several reasons why they should be better. and most of the Bigger ones are Radials.Jet engines that are NON fan jets are Very thirsty. Yes Rover did build a turbine Powered CAR. Thirsty and slow to accelerate. Nev