My 318 burns very rich, need your advice.

you need to get a vacuum gauge and check the vacuum ...

edelbrock make step up springs for the metering rods to allow them to get sucked down if your vacuum is low due to bigger cam...

actually...if you remove the torq screw and small plate that covers the metering rods...start the engine up...you can see if the metering rods are being pulled down while it idles...

also...what is your ignition set at? has the distributor been recurved?