[19bonestock88]

Well, anything that can be done to improve the volumetric efficiency of your engine should improve your fuel efficiency... I would start by raising your compression ratio, match it to the fuel you want... Lots of people can run engines in the 11:1 range on pump fuel(though 91 octane)... After that get some cams ground which move power lower in the rev range(lower lift and duration), and you might see about porting the head/intake manifold, though it might prove harmful to FE...