I have a 14 Rubicon 2 door,2 seater, 3 petal with the 3.6 and the NSG 370 with only 17,300 miles on it, not a daily driver. Planning on putting an Edelbrock supercharger and an Advance Adapter 4 speed in this thing. So will the stock 6-speed hold up? A little insight, this thing is on '40s with a super 60 in front and a 14 blot in the rear both have 5.38 gears, the front is stretch is 3.5 " and a 6" stretch in the rear with 14" of wheel travel. Or should I do a 5.7 Hemi swap with an HP70 8-speed tranny? I'm in California and to smog, this thing might be tricky with the v8. I have talked with Jeep Speed Shop and he is in the process of trying to pass 2012 through 2016 through CARB this winter, not sure if this will work. I'm not looking for the fastest thing out there, but it would be nice not having to downshift on every hill or incline the 3rd petal makes this thing fun to drive, but that could change..

 

No it won't hold up!! These gearboxes are marginal at best. I looked into all this to see if a 2.8R Cummins or my current Chev 5.3 @355HP would hold up. Answer = Nope!! Lots of work but there is a good sticky on it and that is installing the 5.7 Hemi/8 speed you are mentioning. Located in Modified JK section