My way of a mission impossible 318 budget :)

Did you do a compression check?? If the cylinders wonder around ... 95 - 135... I'll say this: The best running, performing, and gas mileage motor will start with sealing valves with good valve guides. All the 4bbl's and cams won't do what a good condition head will do. Next, use the money for a 4bbl intake. That will do you more than the cam and an adaptor trying to run a 4bbl on a 2bbl intake. Last one is free - make sure your heat riser flap in the passenger exhaust is moving freely. I've seen and owned more than one that was rusted shut.