318 MAX fuel economy builds?

Thanks for the input regarding the 413 heads guys I am aware of what i have. All the 413 top end will be used including raised water pump. It is going in an RV so it was made for my intended purpose.

Not a horsepower build to be sure. It is all about low rpm torque for efficiency.

Small ports and valves help keep port velocity up at low rpm to help with gas mileage.