Dodge 318 performance

From Crankshaft Coalition Wiki

well,i'm trying to raise my mpg thru drivetrain upgrades.737 changed for 518 o/d w/lockup.next item to address 410 gears to 353.my question is -changing from 318 heads to 360 heads and adding headers help bring me up from 15mpg to ???.also any other ideas you have will be appreciated!