2.76 vs 2.94 gearing

Hi,how much difference (if any) would I see in performance and mileage switching from a 7 1/4" with 2.94 rear to one with 2.76 gears? This is in a 68 dart with 273 and torqueflite . Not doing this because I want to,but because there's something wrong with the original rear end. Anybody who's experienced both I'd be interested in hearing your opinions. This is obviously not a hot rod,just a daily driver being driven as Chrysler intended jt to be. I'm thinking the difference would be negligible,but I've been happy with the 2.94 gears