Cobra Engineering LLC

Ford has sold the factory "oil cooler" as a cooler for marketing purposes. It is in fact a oil heater. But not all the time. It is designed to get the oil up to temp (ideally above 180*) as fast as possible. Remember that the coolant at startup does not go through the radiator. Instead it is diverted back to the block until the thermostat opens up. This not only gets the temp up quicker, it also heats the oil quicker. This is all about emissions. Also oil works best when it's a consistent temp.
There are many reasons for eliminating this piece. You can run a much larger oil filter when you remotely mount it. Many want to move the thermostat to the upper hose thus eliminating much of the hose maze off the lower radiator hose.
Keep in mind it is always a good idea to let your engine get to temp before driving.
Many problems arise when the oil isn't at temp before circulating.
If you run a after market true oil cooler you NEED to have a oil thermostat in line so you don't over cool the oil.

As you come to expect from Cobra Engineering this piece is superior to all other "plates" on the market. These are profiled on both sides to help the coolant smoothly move to the block.

Also here you see there is two different styles available. Earlier blocks have the smaller opening and later blocks have the larger.

Check your gasket to be sure. Notice the color of the gasket is NOT a good indicator. The small one here is a FelPro and the large one is a Ford OEM. Both are blue. Instead notice how the small one on the top is in line with the mounting hole and the large goes well above it.

Not pictured is two 1/4 NPT ports on the side for your oil pressure gauge or other accessory.