Gear's

How much would switching from 2.76 gear's to a 3.55 gear improve my 1/4 mile time? My combo is a 74 duster with a 360 with speed pro flat top's,lunnati .480 -292 cam 2.02 j head's 600 edelbrock carb and a torker intake,3500 stall converter and 727. My best run so far was 13.38 @103.85