Tire size

Ok I currently am running on the rear a 255/60r15 on an 8" rim and thinking about going with a 275/60r15. Since the sidewall height on this tire is approximately 1/2" taller will it raise the rear end of my car up that much or not much change at all....and going with this size will it have any effect on my tranny or drive train? Currently is 727 with a 9" Rear end.. Thanks