I've been considering swapping gears for some time, and although I've searched the archives and seen many opinions, I'd like to know what fellow thirdgenners really think. I'm currently running a 5-speed LG4 (with some mods to include L69 dual snorkel, KN filter, carb tweeks, cam, intake, L69 exhaust from manifolds back, etc) with 3.23s. The car is a daily driver, mostly around town, but in the summers I enjoy road trips. The last one was 3,200 miles. Should I stay with the stock 3.23s or move up to 3.42s or 3.73s?

JamesC

 

In my opion I think the 3.42 is about the best all around gear for our cars. It gets outta the hole fairly decent and ya still have enough gear for some high speed run. Pretty good gear all around.

 

you gotta go with the 3.73. I have them in my L69 and love it. They aren't too radical, mine are even factory.

Since I broke my ring and pinion, I plan to switch to a 4.10 when I get the funds. A GM engineer told me that, for example, running a 20% lower gear (higher numerical) you don't lose 20% fuel economy, something more like 5%. These were nothing official, just a conversation we had.

My car with 3.73s cruised at 70 at about 2500 rpms. I have 255/60/15 tires too. Having the overdrive in the T5 really helps things out.

I can't wait for my 4.10!

 

tt

 

If you have comments about swaps and why you voted as you did, please list them.

JamesC

 

For the love of ***, don't get 3:73s and I'll tell you why. Unless in the future you plan to do some major mods. Here's my situation. I G-Teched my car on the same road when I had 2:73s and 3:73s.

2:73s and minus my Hooker Cat-back, burnt plug wire and slipping tranny I ran 15.41 @93mph.

w/3:73 posi, Hooker cat-back, tune up, and a somewhat better shifting tranny I ran 15.32 @95mph.

So basically, $800 later I am barely running a 1/10 faster.
What happened is my motor is not a HI-Perf crate motor although it puts out more power than an LG4 or L03, probably around 270hp. However, the cam in it sucks just like the peanut cams in 3rd gens. and the 3:73s are keeping me out of my power range. Now, I probably should have went with 3:42s but I didn't because like most people I thought more gear the better. Well, now I gotta go buy a new cam just to take advantage of the gears, but according to another poster, I'll basically have his same engine mods w/my new intake I have yet to put on, and will be right around the 14.0-14.2 quarter.

Now don't get me wrong, my off the line acceleration is better, which basically only helps my 0-60 time, and if that's what you want then go ahead, but if you're looking for the entire 1/4 mile forget the 3:73s on your motor.

 

About gas mileage, going from 3.08 to 3.89's my gas mileage got better. I did remember to take into account the gear change on the odometer, and verified the calculations with highway driving over lots of mile markers (to school...home...to school... commuting sux) The difference was high 12's mpg before to high 13's then, even with lots of 70mph@3250 I think. Changing to 3.50's, the gas mileage got slightly better again. I'm thinking that in my case, optimum gear (for gas mileage) is slightly below 3.50's.

 

My mpg basically stayed the same.