Alright I know this could go to a couple different spots but I seem to know the Turbo likes different gears. Anyway I have my truck with 29 inch tall tires a turbo and now a 6 speed. I currently have 3.73 gears so those need to change. I am looking at either 4.56 or 4.11 any thoughts?
Thanks
Dave

 

4.56 will give you a hell of a hole shot threw 1st and 2ed then it migh fall on its face but you got that turbo to back it up me I would go 4.11 eather way you'll have a good 60ft if you hook up

 

I have 4.56's but my tires are 31.25". I chose the gears based on cruise speed on the highway in 6th, which is around 1650rpm at 65mph. This is my DD so fuel economy was a concern. Hopefully in Jan I'll be putting on a turbo and I think 1st and 2nd will become pretty much useless. Right now I can't spin the tires even in 1st with mods in sig, but my tires are pretty sticky. If I were you, I'd probably go with 4.11 or 4.33.

 

thanks guys for the quick reply. This is not my DD but I do like to "brag" on fuel economy I have been going on the power tour so it is a long trip. I think I am lugging to much and might step up my fuel economy with lower gears. I am currently at about 15-1600 rpm at 70.
The 4.56 with your tire size puts it about the same with my tire size and 4.11. I dont think there is a 4.30 or so available for my 12 bolt rear end. I thought the same size.
I am leaning toward the 4.11, the first gear in the T56 is pretty tall, plus the double over drive.

 

4.11's should do well. 1st is tall, but with a turbo you will get through it quick or just spin

If you haven't gotten the trans yet, the gear ratios of the GTO T56's a better suited for a truck.

 

what rear do you have?

 

which 6sp do you have also? looking for the gear ratios

 

Jonathan,
I have 3.73 this is in my 1968 chevy pickup so it is a factory 12 bolt with an aftermarket eaton posi.
This is a standard T56 out of a Camaro so the ratios are. 2.66 1.78 1.30 1.00 .74 .50 for 1 thru 6.

 

here is a cool excel program I did not make this it was found on the internet... i dont know who to give credit it to.
We may want to put this somewhere easy to find.

 

Ill request it.

If you plan on doin alot of driving.. id shoot for 1900-2100 at your perfered speed.. say 70-75ish.