Not all pre 2011 mustangs were bad. 2003 Terminators (Cobra) will destroy most cars in 1/4, and they had an independant rear suspension too (The only mustangs that did I think). A factory iron block with forged internals helps a bit too.
In any case, Mustangs will pwn just about any japanese car in drag racing, and while it would be nice for the Z to be a bit more competitive, it's just not a great platform for this purpose. For the mustang haters in this thread, remember one thing:
Ask any racer, any real racer. It doesn't matter if you win by an inch or a mile; winning's winning.
