Is this a good deal? Will it do what I want? Carb/Intake

Put a good tuneup on what you already have. Tweak the distributor and the carburetor and you should be in the 20 to 25 mpg range.
My dad and I were always tweaking the 318s for mileage. 21-22 was an average. Our 78 Volare with 318 automatic used to get 26 and 27 on the interstate. That's was with the original carburetor and distributor and a lock up transmission.
Super tune it.