Best Gear Ratio? Nd I Need More Hp

[josejuan_602]

i have a 2003 gmc sierra Z71 i recently went from a 5.3 to a 6.0 i did head nd piston work .30mm over i have ls1 cams on it elderbrock headers flowmaster full exhaust k&n air filter and a custom tune from a local shop! my queston is what would b the best gear ratio for my my truck i like speed but i also like to go offroading also any ideas on what i can do to get more hp out of it?????

[Mckenzie]

How big are the tires you have on or are thinking about getting?

[Stevens03]

My suggestion would be if your going 33" tires, then 4.10's would be good and if your going 35" tires, then 4.56's

 

And welcome.

[josejuan_602]

How big are the tires you have on or are thinking about getting?

 

 

 

well i have 20in chrome rims on nitto mud grappler tires dimensions are 33x12.5r20lt

[josejuan_602]

My suggestion would be if your going 33" tires, then 4.10's would be good and if your going 35" tires, then 4.56's

 

And welcome.

 

 

 

 

so ur suggestion is 4'10?? cuz i have 20in chrome rims on nitto mud grappler tires 33x12.5r20lt nd another question if u could haelp is what bout the front diff?? do i gotta change the ratio too?? and how much of a diff would it make!?? srry i really dnt knw much bout this stuff im triying to get familiar with all of it

[Stevens03]

What gears do you have now? If you don't know, look in the glove box at the RPO codes.

 

Look for

GU6 - 3.42

GT4 - 3.73

GT5 - 4.10

G80 - Factory lockers

 

And yes, since your trucks a 4x4, you need to swap both front and rear.

[Carder09]

What gears do you have now? If you don't know, look in the glove box at the RPO codes.

 

Look for

GU6 - 3.42

GT4 - 3.73

GT5 - 4.10

G80 - Factory lockers

 

And yes, since your trucks a 4x4, you need to swap both front and rear.

 

 

And not sure if they made this code for that year but I have the GU5-3.23 :..(

[Stevens03]

And not sure if they made this code for that year but I have the GU5-3.23 :..(

 

I believe thats for a 2wd pickup and why i didn't list it.....

[josejuan_602]

What gears do you have now? If you don't know, look in the glove box at the RPO codes.

 

Look for

GU6 - 3.42

GT4 - 3.73

GT5 - 4.10

G80 - Factory lockers

 

And yes, since your trucks a 4x4, you need to swap both front and rear.

 

 

 

i checked and i have the gt4 wich is 3.73 do u still recomend the 4.10 gears??? how much do they go for?? nd do you knw of any website where i can get them!?? thank you!

[tyhuck]

With a 6.0 under the hood, you should have more than enouh power to turn a 33 easily with a set of 3.73 gears and mixed off and on road driving. I wouldnt bump up to a 4.10 until 35 or taller.

 

However, if you are towing constantly or are hitting pretty big offroad trail obstacles, then you should gear down.

 

Ide suggest running the 3.73s and see how happy you are with that. If you want more grunt, then gear down. No sense in spending money you dont have to. Besides, my old 96 2500 had 3.73 gears and it would roll a 32 without batting an eye, and run like a scalded ape. And that was with a stock 350 under the hood.