10mm is not much and I have ALOT more weight over the rear-end than a pickup.

I spoke to tech that plan to install for me. Some people say I should go 3.90 gear but I think it not good for turbo? I was thinking about go 3.73 but some people say go 3.90 what is your opinon, Im running 275/45/20 but will change to 17" wheel 1320 someday. Also how much good price for package gear/locker auburn or eaton/ install kit?

That is a ~30" tall street tire. Unless you are planning to make more than 700-800 ft/lbs of torque, you would do well with a 4.10 gear ratio. At 75 mph you would only be turning 2,600 rpm. Shifting at 6,500 rpm you will get to 50 mph in 1st gear, 90 mph in 2nd and assuming you lock the converter in 3rd you could still reach 140 mph and be under 6,500 rpm before having to hit overdrive.

A 28" tall tire on those 17s would work well assuming you trap in the 110-130 mph range at the track.

IMHO run more gear even with turbo

So you guy think I should go 4.10 what about 3.90? Hp I think will make closer 600-700 hp it's up on my motor/turbo peaking.

What about auburn or eaton you rather to chose ?

ran 410s with a turbo setup with 28s and trapped 130 on 12.5 psi

my combo is saying 373 with a 30" for 170mph trap target........think about that

I ran 3.42, 3.90 and 4.10s with my old turbo. 4.10s were the best and 3.42s were freaking horrible.

Shit you guys are making me wanna ditch my 3.42s asap for some 4.10s lol. I'm going to soon, but I'm running a maggie instead.

most 342s arent making enough power to justify them

Curious 4.10 what top speed they can make it?