318 MAX fuel economy builds?

I would be careful using Rhoads lifters with a mild economy cam. It could be counterproductive because it reduces valve lift at the lower rpms, where economy is made. Every engine has a 'sweet spot' where everything melds for best efficiency & you are seeking the highest efficiency from the fuel used.
That's why I want to use a 215 to 220 at .050 cam. It's a nice street cam that becomes an economy cam below 1800 rpm with Rhoads lifters.