car wont start
 

I have an 85 grand marquis with a 302 5.0 engine. recently i decided to change the valve cover gaskets. i took the park plug wires off and im not sure if i put them on correctly. can someone tell me correct order of them? also my battery was dead and had to get a new one, so i did. now when i connected the battery terminals there is a hissing sound. like the one the fuel pump makes but it wont go off unless the battery is disconnected it comes from where the carburator is at and i could also hear it in the back of the car what can it be?

The "constant on" fuel pump noise could be from either the fuel pump relay stuck on "run" or the fuel line regulator (inside the top of the throttle body) check valve is defective (regulator needs replacement). The fuel pump relay is located above the driver's side front wheel cowling. One relay is used to power the engine computer and the other is the fuel pump relay. Pulling the relay out of its plastic case, you can check to see if the points are stuck "on". The wiper contacts arm should be up (away from the relay coil) in the "off" position.

The plug wire connections and firing order can be found at
http://www.302w.com/Firing-Order.aspx

If the plug wires are not connected properly, a backfire can cause a momentary flame at the bottom of the throttle body which can permanently damage the injectors.

If the link does not work, search engine "mercury 302 firing order"