Just recently had spark plugs, boots, etc.. replaced. Everything except COPS. I know I should have had them replaced as well, but didn't have the money at the time due to selling and buying houses. Now that it is all coming close to the end I was researching prices for COPS. I am definitely going with the Motorcraft brand. Was looking on Rock Auto and found these. (Bottom of page). It says DG508 and DG540. Are the DG540 a replacement? If I don't get an answer here I will probably ask someone from Rock Auto. I just wanted to see if anyone here knew first.