318 MAX fuel economy builds?

A little progress on my 360 mpg build. I got a .040 74 360. It's getting 318 rods and balancer and getting converted to internal balance, That's happening now. I used the factory style dish piston. I could not risk detonation issues. I picked up a performer egr manifold. My machinist is building me a block for the egr so I can tap into the egr before the valve and plumb it into a 1" 4 hole spacer. Running a tube from the passenger side heat crossover into the opposite side of the 4 hole spacer so the heat will circle inside the plate. Putting a 4 hole 1" air-aid spacer on top of that. milling the spacer the same as before but plumbing coolant through this spacer. Scoring the port walls of the intake and head. I just picked up a set of 302 heads that I will be massaging. Gasket match and mild porting in the pocket. polishing the chamber. Running a 216-220 @ .050 Hughes cam with Rhoads lifters and 273 adj rockers. avs2 carb with an Edelbrock distributer which has adjustable mechanical advance and adj vacuum advance for a nice fine tune. 67 cuda 2.94 gear but the a500 is going in shortly after the 360. 3.55 gear. Hoping for 20 plus.