IOP if your familiar with FL tracks it's for Mills Pond in FtLauderdale. I don't go by the instructions for shimming the diffs. I found it WAY To tight . people will tell you it will break in and it may but I don't buy it. To tight will also cause premature wear IMO. I don't mind if they are a tiny bit notchy but will still roll. you can always add shims later If you need to take up driveline lash