How much difference will it make?

Dana67Dart said
I'm no drag racer, but my gut says your rear gear at 4.10 is too much, taller tires or smaller gear.

He's running the a500 overdrive. It should tame the 4.10 gear. I would leave the gear. I run 3.91's with a 727 and to me seems fine. 28" rear tires help in my case. However, highway driving is limited for my liking.