A standard transmission 2.56 first gear would be great. But if you referring to rear axle not so much. The 3.73 is a good rear gear with a low 1st gear.
Torque multiplication with automatic and converter foot brake, change to line lock will make the biggest difference.
Actually your question is too vague.......
Faster 60 foot times, if you can keep it hooked up and not blowing the tires off it at the line.
As far as et it depends on so much more.
Where is the power band? Where will the new gears put the rpm in the power band in each transmission gear before it shifts. what are the transmission shift points(automatic), Will the gearing say 456 or the 373, when trans shifts into 3rd, be at the low end of the powerband through the lights, or outside/past the powerband.
When going through the lights you want to be at or near the power peak. to far past it, it'll fall on it's face, to low in the powerband it won't pull strong at the top half of the track.
Application dictates gear ratio.
for economy, the final gear must provide adequate cruise MPH and RPM for minimal friction and minimal wasted energy.
for 1/4 mile racing, the rear gear ratio is determined by the weight, power and rpm capability of the vehicle, e.g. 3000lbs 500-700rwhp, 27.4" Tall tire, max rpm 6300rpm, the car needs to be able to achieve at least 140mph so the use of a 3.2 to 3.4:1 ratio would be ideal. A 3.73 would not work for that application.
For 1/2 mile or 1-mile racing, a 2.70 or 2.50:1 might be required to get the mph 180 200 etc...
Some engines can spin 9000rpm or more so the gear ratio always needs to adjust to suite the ability of the engine/trans and weight. Some vehicles go up and down in weight frequently (trucks carrying loads) and this too must be factored into the ratio of the differentials and trans.