You wouldn't want to use copper head gaskets as a method to lower compression since that opens up the quench inside the combustion chamber (which kills power gains). A healthy powerhouse needs a tight quench area (area where the flat part of the piston meets the flat part of the head). The only correct way to lower the compression without killing the quench is to open the combustion chamber up in it's area or by using a dished piston (that is NOT dished in the area of the quench). Now I'm just giving all this info based on motors that have a quench area in the first place. I've never seen the combustion chamber on my Duratec yet, so I don't even know if it has a closed chamber design in the first place, so if it does NOT, and it is an open chamber design, then it's too late anyways. That would make this engine doomed for building and trying to gain power in the first place. In that case, a copper thick gasket couldn't hurt performance any worse than the open chamber combustion chamber design already would.
Also, I DO recommend lowering the ratio down to at least 9.8 to 1 (with 10 to 1 being the highest) if your gonna run pump gas (92 oct). This is where your maximum power gains will be realized with proper tuning. The amount the timing has to be retarded and the amount the fuel has to be richened in order to counteract detonation will be less power than the optimal fuel and timing curves using the maximum recommended compression ratio. Believe me, I experimented with all this stuff when I used to toy with Stangs a lot. Maximum power was at 9.8
Better breathing is the key to power. (Higher compression too, but only with better gas)
