318 MAX fuel economy builds?

GM only used it in their Cadillacs (so far as I know), plus they had issues. Originally developed by Lotus for GM, Lotus wanted a bunch of money for the project. Instead, GM bought Lotus, pulled the Northstar program, then sold the rest for pretty much what they paid. It has been plagued by head gasket issues, where the head bolts in the aluminum block eventually pull. Main bearing failures have also been attributed to structural integrity relying on threads in the aluminum block. I have one here where I drilled out the head bolt holes larger, tapped them, then used head studs with a larger clamping force.