Help me build a 318!

Not trying to hijack your thread and I know you are asking about 318's, but I just built my 71 Charger with the same thought in mind. What I did is a 360 bored .030, 9-1/2 flat top pistons. Windage tray, Melling m72 hv oil pump. Crane energizer cam with 216* duration .454 lift, 3 angle valve job with port matched heads, Eddy RPM intake with a 600 AVS carb, orange box, headers/duals. 727 with factory high stall converter 8-3/4 rear with 2.94 gears. I am getting 16 mpg so far and still have a few more jet/rod changes to make in the carb. and other tuning adjustments. My goal is to match my 09 Ram's milage, which am very close to doing.
I think you are on track with your goal and a good cam will help you bring it closer. You could also call different cam grinders and get their recommendations for your goal. Good luck and look forward to seeing your results!