well,that figures. it probably is 5.5 mm,because that is the only one I don't have I did take the heat sink out with the module. looks like I get to go socket shopping tomorrow morning after work. The "goo" that is on there if it is original,does that need to be replaced? is it dielectric grease? my new motorcraft part did not come with any goo or dielectric grease. should I buy some to put in between the heat sink and the ignition module?