I was there when Ford debuted its new-for 1999 Mustang Cobra with its "revolutionary" new independent rear suspension. The IRS was a first for the Ford Mustang, and it was a move that Ford's brass believed would allow the "new edge" Cobra to compete with cars like the BMW M3 for supremacy in the budget super car market. I also remember the very first question that was asked: Will a Ford 9″ bolt in? It was the first question, right out of the box … and it seems like someone at Ford remembers. The new-for-2015 Mustang is going to hit dealers with a new independent rear suspension late next year, and it seems like Ford Racing will have a 9″ live axle option ready.
According to a Ford Racing employee at PRI, the live-axle version of the 2015 Ford Mustang is expected to debut at next year's PRI show as part of a new "body in white" program intended to attract serious racers to the platform. The body in white 2015 Mustang will also serve to take some of the shine off of bitter rival Chevrolet's current COPO Camaro and body in white Camaroprograms.
Once the live-axle 2015 Mustang racers are out "in the wild", the parts needed to convert street-going Mustangs from independent rear suspensions to the 9″ setup should become available through Ford Racing and participating dealers. Back in 1999, SVT engineer Eric Zinkosky said the "new independent rear suspension (was packaged) in not only the same space as the solid-axle design, but we had to use the same suspension mounting points. We virtually 'reverse-engineered' the IRS from the known suspension hardpoints, and we had to keep everything inside the same box." Assuming similar thinking went into the upcoming Ford Racing 9″ suspension for the bodies in white, getting a solid axle to help get a high-horsepower Ecoboost Mustang's power down should be a lot easier than many have feared.
About my source: While I have opted to not give his name, this information came to me from a Ford Racing employee on-hand at the 2013 PRI Show yesterday, 12DEC2013, when I asked if I could look under the hood of the (supposedly) 4 cyl. Ecoboost Mustang spinning on the big lazy Susan at the Ford Racing stand. He said no. I told another PRI old-timer the story about the 1999 Cobra IRS reveal, which the Ford Racing rep overheard. He laughed and said, "Yeah, that's not 'til next year. We'll probably announce it at the same time as the body in white program …" but he got called away before he could say "That's off the record." Take that how you will.