I'm actually at 2450 rpm @70mph and 2700rpm @80mph

 

Wasn't there something different in the gears with gearing a 2010+ truck? If so, what's the best place to buy a set for the newer trucks?

 

I have an 08 that came out with 3.23s and I was thinkin about 4.30s until I seen this post. I do quite a bit of HWY driving and 2700 is a bit much. I'm running the same size tires and I have the 4l60e so where would my RPMs be with a 4.10?

 

What size tires?? the 305/40/22?

http://www.f-body.org/gears/

 

Your running about 1700 at 70 right now??

2250ish for 4.30s at 70

 

4.56s, no doubt. I already wish I would have went there myself. Spin the **** out of it man, LSXs can take the RPM at 90mph all day long and not even break a sweat, they aren't like an SBC designed in the 1950s...

 

If you go from 3.42s to 4.56s, don't forget about what that does to your driveshaft's critical speed. If will be lowered by 33%.

 

Can't wait to see how 3.23s to 4.30s feel...

 

Yes.

Yes its about 1700. It's so sluggish from take off and cruising around 55-65, just driving up the slightest incline, it kicks down from o/d and goes into 3rd. If it's too much sometimes it drops all the way down to second. This truck barely pulls its own weight.

 

with 4.56's I'm running 2200rpm @70mph with a 35-12.50/17 and i'm wanting 4.88's now. Go bigger than the 4.30's