Fuel economy (odd ball)

Right now my car is getting about 7 kilometers a litre but the valves need adjusting (hopefully saturday) the rear most likely is getting worn out, and the engine doesn't run perfectly smooth (most likely uneven compression on the cylinders) good car over all though especially right now driving in the winter the suregrip comes in handy. It needs fuel lines as well but I really don't have anywhere to work on it and I don't like crawling in the snow to do fuel lines. I changed the heads to a newer one with small spark plugs and no druel tubes don't know if that matters it seems a little smaller but I had 2 bad valves on the old head.