| So since they are making the 4.10 gears again I figured I post these pictures to illustrate what you are getting or what you can expect as far as RPMs and etc. One thing many forget is what your final wheel ratio to Engine speed is. And that is affected by all the gear ratios in the tranny, diff gearing, and wheel size. Many of you who went from stock wheels to the after market 18s have noticed how sluggish the car became, people will tell you that is because they are so much heavier than stock. But I feel that is not the case it is because your final ratio changed. Here is what our cars do stock. 
I will use 65MPH as a reference, as we can see this is stock wheels, and stock rear end gearing. We see 65MPH at around 2458 RPMS. Now here it is if we just put on 285/35R18s. 
As you can see we drop down a few RPMS to 2346. Doing this we see that are cruising at lower RPMS. Which I think gives us a better feel when up to speed, probably even better fuel economy. Now what happens if we have stock wheels and 4.10? What were are now on RPMS and etc? Well first of all we have a real Torquey car and it would be a little more fun at all speeds except just cruising were we would see higher RPMS. As you see 65MPH is at 2729 that almost 400 RPMS more than a stock diff with 285s.. 
So our final option is what I am using which is to run 285/35R18 wheels with a 4.10 Gearing. I feel this is the best compromise as it is only 150 more RPMS than a fully stock configuration, you get a little better torque feel. To me it really woke my car up in the lower RPM as I don't see any real power until 4K RPM range (at which point it continue to climb until 8.5K ). 
So basically I am recommend anyone who has upgrade wheels to do the 4.10s.. Also swear that my gear set is quiet there are some who say BS but I had my gears, custom shimmed (the factory specs are not good for leader gears, custom shims have to be made, don't expect to just slap them in and be good. This not just a remove and replace, this more of a massage, and etc.) For those interested I had my gears done in an Atlanta Driveline shop, who has experience with whiney Leader Gears. I have posted this info in the past but I hope it helps some.. The tranmission calculator is available here so you guys can play with.
Z32 Transmission Calculator Maybe put some DUBS on and see how bad your gear ratio would be with a 4.10 set on? Hell why not put some 10' Tires like this beast over here :-)
Big Foot 4x4
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Diff gear Ratios.. related to Leader Gears - 
