If the gearing puts you in the rpm range where you make the most power for the longest time, you'll go faster. Locking the converter could possibly bump the mph up depending on the setup.

The less transmission gears, the more it makes a difference. If you have a 3 speed auto (non-overdrive gears_), having 2.73 vs 4.11gears (assuming 4.11 is the right gearing) - could be 3 to 5mph in trap speed. If you have a T5, the difference would be a bit less as the gear spacing in the trans is better - even if the launch is so-so.

Keep in mind that the new generation of auto transmissions have up to 6 non-overdrive speeds, so gearing may not be as much a factor. Having a 4.5 1st gear (and close gear spreads) with a 2.73 rear is pretty much the same as a 2.75 1st gear (WC T5) with 4.11 rear gears.

Max acceleration is attained when each gear shift drops the rpm right into the meatiest part of the TQ curve, with the engine hitting peak hp right as it passes through the traps in the 1:1 gear. With the new transmissions, it may be a lower gear - but the same performance. So many variables!