I didn't see if you acquired the mustang engine harness, but it's different as well. Then you have to look at the oil filter adaptor as well. There is a lot of small differences that some people don't know. If you plan on the gear change, first ask if you are going to ever put a supercharge on it, or if you ever intend on revving it up to 7k then I would say do the gear change, but make sure you get the correct ones. Ford changed the thickness of the f150 to gt but they are a little different in diameter. So make sure you get the right ones.. gt gears don't fit in f150 housing. Don't know if you read any of my posts but I had to do a lot of research that many people didn't know about, so if you anything pm me, I'm not on as much.