Would it be worth it to swap from a 2.73 to a 3.42? Car is my daily driver and might see the strip once a year. Any opinions are welcome. Thanks.

 

Hell yes it's worth it IMO lol!

 

Defiantly worth it dont think twice, i go with 3.73 lol

 

I was reading that there isn't much difference in 3.42's and 3.73's so I figured I'd try the 3.42's to save on the gas mileage a little bit. Anybody know what the mpg is with 3.42's on a stock internal f body?

 

Well since a lot of f-body LS1's came with 3.42's from the factory, then i'd go off the manufactures listing. I think they were rated like 17-18 city and 26-28 highway. In fact your city mileage may increase a tad with the steeper gear

 

that sounds pretty good to me. I see on here all the time about guys getting stall convertors. But it's my DD, stock cam, and I rarely ever launch my car so I don't see where a stall would benefit me any. So I figured some new gears would wake it up and still have the same street manners.

 

Yeah it sounds like for your purposes some gears with the stock stall would be fine

 

I'm still interested in knowing what the mpg's are for the people with automatic trannys and 3.42/3.73 gears. Anybody out there?

 

Damn, I'm just bolt ons and I get roughly 20 city haha.. But in this town everything is within maybe 1 mile of eachother. Small *** city.

 

i made the swap and it was really nice. I gained a coule mpgs putting around town but on the hwy you will lose some. I cruised at 80 pretty steadily on the hwy since florida traffic moves quick. I used to get 24.5 with the 2.73's doing 2k rpm at that speed when I went to 3.42's it jumped to 2500 and i got 22-23. now with the 6 speed and 3.90s im up around 26 lol

 

I didn't notice any mileage difference in town. With 3.42's on the highway @ 75-80mph average, I got 23 with the stock converter and 24 with a 9.5" unit.

 

Did you guys do the labor yourself or took it to a shop? and if you did do it yourself, how hard was the swap?

 

If you are not a experienced mechanic (and have done it before) then DO NOT do it your self. You have to have a lot of different measuring tools and you have to shim it exactly right. It is worth it to pay to get it done because driving 100yd to a mile can destroy your gears depending on how bad off they are. Been there my self just pay for it. Its not just a pull the old out and slap in the new kind of job.

 

Well my dad(mechanic for 30+ years) was gonna help me do it. But I'm not positive if he has all the necessary tools. How much did it cost to get a shop to do it for you?

 

I've done it once on a ford rear because it had screw caps instead of shims like the gm does. I didnt do it for my 3.90's because I simply didnt have time, with the right tools and instructions you can do it. you will need an inch lb tq wrench, bearing press, new crush sleeve, bearings, and a dial indicator with a good mount. If you take your time and have some know how it can be done. installs usually run around 300-400 depending on where you are and what they do

 

Is it a must to drop the rear end when swapping gears?

 

no it can be done in the car... you will also need a shim kit which I forgot to mention. the inch lb torque wrench will measure pinion bearing preload. pinion depth into the ring will be changed by pinion shims and backlash will be changed by carrier shims

 

Gotcha. Thanks for all the help guys. It's really appreciated.

 

If he is a machanic he can proly do it with limited tools. Just using experience. 300-400$ for a shop to do it. Ask him questions about it I'm sure he knows more about it then many of us.

 

yea i asked him this morning and he said he could help me do it with no problems. Now I just gotta decide whether to go 3.42s or 3.73s.