too big a difference in front to rear height?

What's the biggest difference there should be in tire height from front to rear? Im running 275/60/15s in rear which says they are 27.9 inches tall but measure closer to 27. Im looking at fronts that are 165/80/15s which it says are 25.3, so would that be too big a difference? My old fronts were around 26.5 inches and I think a little shorter would look better. Just seeing what other people think or have experience with.