If you're mounts are in good shape, you're probably okay. I've got about 1/4" on mine with stock mounts and most would say it's too close, though it's never touched - even hard on the brakes on a 107mph pass at the track. Of course I've got a limiter bolt on the driver's side biscuit motor mount. Not sure if that helps control fore/aft movement much though.
If you're worried about it, you could always make up some type of fore/aft limiter.