As usual, I may have a small crisis on my hands. My car is on the lift waiting to have the rear housing rebuilt and 3.73s installed. I believe however, that I may have the wrong gears waiting to be put in. I bought my FRPP from Blue Oval Industries whose website said these gears would fit "any Ford 8.8" rear end". I was looking through the MN12performance website and found that not all gears will work due to a circlip step needing to be machined into the side gear for our IRS halfshaft circlips to sit in. The PN for my gears is M-4209-F373N. It is listed as a Mustang 8.8" rear gear set (but for "any Ford"). I don't have the gears with me so I can't verify if they are wrong or not. Can anyone tell me by the PN if I am screwed and need to get another set ASAP??? If yes, then what the hell is the right PN? I called Ford and they didn't differentiate between my gear set and a non IRS gear set...go figure!