mileage. the harder i try the worse it gets...

The two things that jump out at me most here are the carburetor and the open plenum spacer. Those Edelbrock carburetors are not made for mileage. With a square bore design, they just are not the best for mileage. Plus, with that open plenum spacer, I think you are killing yourself on the bottom end....basically the WHOLE operating range of that engine. A spread bore carburetor with small secondaries with NO spacer would probably benefit both mileage and performance by a good margin. Of course, that will require a manifold change, which I am not sure you are willing to do.