Ok to grind carbon soles?
 

I have a set of Vittoria carbon soled shoes for old style Time cleats. I want to install Look cleats but a 7/8"X 1/4" rail surrounds the rear of where the cleat would mount. Will I kill the strength of the sole if I take a angle grinder to this rail so I can mount my look cleats? The kid at the bike shop suggested this as a fix when I described my problem when looking at their new shoes.

You could, if done very carefully. The more important thing though is to make sure you wear a good filter mask so that you don't breathe in the carbon dust particles.

7/8th x 1/4? do you have a pic? it seems you are talking baout removing almost an inch of material off the sole.