First, tell us what year car you have so people like me who intend to help don't have to look up your car domain page from your sig, which BTW does not work.
Second, the oil on the plugs is from hardened seals under your valve cover. They are not part of the valve cover gasket, they are ordered separately. You have 8. The best place to order these from is five star ford in Scottsdale, AZ. Ask for Max, tell him you know Eli in Worthington. You get a good price on all things Ford.
Third, the noise you are hearing could be a bad lifter, a bad rocker, piston slap, a rod or just low oil. These things are difficult to diagnose when not in person. How many miles? Has anything happened recently that would cause this? Have any modifications been made recently? The more information you can provide, the better others can assist you in diagnosing your issue.
My guess is it is an oil problem, either low oil or an oil passage is blocked to a lifter. Good luck. If you need help bad, PM me. I have had a lot of 4V Fords apart.