318 MAX fuel economy builds?

Those look very nice and yes happy. I don't need 400 hp. Just good mileage and a lil power when needed. Who on here is willing and capable of doing a set of 920's like this for a guy? What size valves did you use? And who has a clean set of these for sale to build upon? I can always slap a set of J heads on later and I'll have a great set of 920's for some ones 318 or?