The Auto industries went through this same thing in the seventies , Manufacturers tried mileage cams ,Crappy intakes that just killed power and a lot of other ideas . The bottom line was if you want economy then you need a car with a smaller engine . all of these ideas did make improvement but the engines were so gutless that you might as well just install a 4 banger . Those were not good times for hot roding but it sure looks like it is coming back . Do we see a 4 banger Mustang and no V8 option just like in 1974.