I have a 12 model Sierra 4.8L

Mods:
BTR NSR CAM
SPEED ENGINEERING LONG TUBE HEADERS
CIRCLE D 3000 STALL
STAGE 2 TRANS 4L65E
3.42 Factory gears
20 inch wheels on 275/55/r20 Not sure what I am going to do wheel and tire wise
JRX TUNE

Looking for input on gearing? My next move is going to be either TURBO setup or SUPERCHARGER. With that being said I am going to do the gears first like right now but I cant decide. Do I just go 3.73, the middle 3.90 or go 4.10? Im seeing a lot of back and forth and just send it but just wondering about the experience people are having with the 4.8 turbo/supercharged and their gearing.

Thank you for any input

 

Is going to be a street car or something you want to drag race?

You can put of alot of this information into a online calculator to see what your top speed will be and if that will be enough to pass through the beams in 3rd gear still.

 

My 07 had those size tires and wheels and I went from 3.42's to 4.10's when it had 5.3, turbo, 4l60 and it dropped .64 sec in the 1/8 no changes and identical weather. Highway driving was not buzzing at all. I would do 4.10's positively with the 4 spd. Think the calculator is a great idea as I never ran 1/4. Wallaceracing.com online calculators is awesome.

 

Its pretty much gonna just be on the street.

 

 

I'm pretty sure those are 32"s/ Don't recall mine being anywhere near that. Better check the calc.

 

 

I meant "I" better check the calc. Lol. As it turn out mine were 31.9's (Goodyear) and I was happy as I could be but I see there are 31's as well. So, depends. I was at 2100ish but 31's would be probably 2200ish. So 3.90' could also be a choice depending on how much hwy. Side note...I got 21 mpg back in the day with turbo. A calculator is definitely out friend