i have a 2003 gmc sierra 1500 with the 5.3L engine, i have a cold air intake, throttle boddie spacer, superchip cortex, and a highly modded transmission......i dont have the power off the line i am looking for and that is what i am here for i am wanting to know what gear ratio i should put in my rear end to make it "get up and go" i guess you could say......and what else could i do to it to make great performance gains other than forced air induction and breaking into my engine???

thanks for the help and time, brandon

 

If you use this truck for everyday use the 4.10 would be better than the 4.56 unless you are not concerned with fuel mileage. My buddy has 4.10's in an 06 among other things and its an animal!

 

4:56 are great for getting serious get up and go. i have had 4:10's in two trucks and my wifes H3 had 5:72 which will get you some really good off the line performance but gas mileage goes away. is this truck just your daily driver? i like my 4:10 for daily driving with stock tire size i think that when i put a lift kit and big tires im might go to a lower gear ratio just so i can keep the amount of torque that i get now.....