"slow" could be soo many different things. To address your question you can swap gears depending on the current rear axle set up you have. If the other 3.73 gears are set up in another axle it would probably be easier to just swap the axle as it wouldnt be much more than a take out and replace process. Do you know what gears are in the car now? Does slow mean your getting rpms but the rest of the car isnt responding to it. Are you getting any roughness in the engine, meaning rough idle, rough start, fluctuations, bad pedal response? More details gbet better responses. We're all glad to help.