[Fat Charlie]

Welcome!

Hmmm... Lose anything that gives downforce, find some way to get narrower, less grippy tires, and if you can do taller gearing, do it. A powerful engine not working hard can afford the taller gearing, and that'll give good results with the right driving technique (as long as you do get the manual).

I never miss a chance to recommend against modifying the engine innards. Even in a sports car with a manual, there's too much slop between the combustion event and the miles the car travels on a gallon for a custom designed camshaft to be the first, tenth or even fiftieth place I'd look to increase overall efficiency. I'd recommend an engine swap first.

If you want to get amazing mileage in a cool car that nobody thinks of as an mpg machine, do it. That's awesome. If you're an engine nerd and want to design a camshaft that will totally change the character of an engine like this and need to radically modify the rest of the car (and your driving style) to hit a great sounding mpg threshold to show off your engine design skills, do that too. I think that's more awesome.

I'd be tickled to drive a Vette hacked for mileage. That'd be more fun than driving a stock one.