2.94 gears... how painful will it be?

I used to drive from Pittsburgh Pa to Denver Co.(about 1600 miles) in a 70 340 4 speed Duster. Used the 2.94's and ran about 62 mph (back when the speed limit was 55) got around 20 MPG. I liked it as a all around gear.Even drag raced at Bandimere. I found some 3.91's.Would switch it out for 3.91's in the apartment parking lot to go racing. I was allot younger then. Anyway 2.94's were good for my Duster and me.