Whats up everybody. New to the site. Lookin to get some insight to figure out the widest tire I can put on the rear on a factory 2000 gmc Sierra. Truck is lowered 2/4 and has a 275/50/17 radial. It's a rcsb turbo 4.8 with th400. Truck won't hook for anything on the street and that's where I want the truck to work. Any help would be appreciated

 

What other suspension mods are done? Traction bars? Shocks? Rear gears? Is it a locker?

 

has 4.10 gear traction bars and will hve Calvert split monos and Calvert shocks within 2 weeks and the rearend is a built 10 bolt with a locker.

 

I came across thread from several years ago stating calvert didn't recommend their split monos for the trucks...too heavy

 

I'll hve to talk that over with them. I've talked to a few people in my area that recommended them. May not be the way to go.
I just want the truck to be the best it can be on the street. Any thoughts on how to do that??

 

Drop gears to 3.42. It will allow you to control the power on the street a lot easier

 

The truck is stock bottom end 4.8 with stock heads an ls6 cam. With that gear would the truck still be able to get off the line??

 

Depends...if you have a converter it should and it may help on the street. Hard to say for sure. I on the other hand went 3.42s to 4.10s with my 07 5.3 and dropped .64 in the 1/8th but it was 4wd with 32" tires 275/55/20s.

 

What size is your turbo? You might need a bigger stall if your turbo spools later in the rpm band but that's to much gear for a turbo truck on a 275 tire on the street

 

Turbo is 80mm. Stall is around 3600. Does bt 32. 2 step is at 3100 and depending on air temp I can't even get in 2 step on street cuz it will spin for 300 feet. IF it's cool out truck will break the tires around 2200 if it's a lil Warmer it'll wait till bt 28-29. I just bought a wider tire as well but its shorter. Got a 315/35/17. Gonna change it all next week