i have 2.73's and i was wondering how much 3.42's and a posi will take off my et? thanks

 

i gained like 6 tenths and 6MPH from 3.73s, posi, tbichips.com stage 1 chip, and a crank pulley. Im guessing the gears were good for at least 5 tenths of that.

 

i lost 1 tenth going from 3.08's to 3.42's. my MPH stayed about the same. but for where i am going 3.42's or steeper is what i need.

i am sure this is going to rehash the gear argument that has been going on in this board for a while, do some reading, and make your own descision on gears.

 

i picked up almost 6 tenths going from 3.08s to 3.42s. (best of 16.59 before, best of 15.94 after). going from 3.08 to 3.42 doesn't seem like much, but it makes a HUGE difference, not only in performance, but daily driving as well. i can tell you this, i wouldn't be comfortable with any more gear than this if i did any significant highway cruising.

the general rule of thumb is the more torque you have, the less gear you need. lt1s and ls1s don't make a lot of torque. that's why their base manual trans gear is a 3.42 instead of a 3.08. their performance gear is a 3.73 while a 3rd gen's was 3.42. both tbi and tpi make much more torque in relation to horsepower than 4th gens. 4th gens remain streetable with those stiffer gears because they have that 6th gear.

 

yes, IMHO, and i have said it before, 3.73's are too much gear for most of our cars. in stcok form

i think that 3.23's are a great one, 3.42's are a good choice, especialy if you plan on any mods.

 

There is no performance gear for 4th gens. Any M6 car came with the 3.42's. Now after cam swaps many guys go with 3.73's (I think that is what you meant) and some LS1 guys go with 4.10's. The LT1 makes a ton of torque all across the board. Although it is advertised lower than the L98 it makes about the same and it comes in at a very low rpm and stays really flat. Remember lots of auto 4th gens came with the 2.73 gear like 3rd gen's did. TBI and TPI make great toruqe in relation to their HP but that is because they fall flat on their face after 4000 rpm. The stock TBI and TPI desing does not promote high rpm power. Whereas the LS1 and Lt1 do, yet they still have the same amount of botom end. It just doesn't feel like they have low end because the high end is so wicked. But trust me, both cars have serious low end.

 

Yes there is. The 93's could be had with a 3.73 rear gear if ordered that way.

And my '94 Z28 came with a T56 and 3.23 gears. The 3.42 was an option, but only with the 1LE package.

 

I geuss I am not familiar with the 94 model. Maybe they did things different that year. I do not have the 1Le package in mine but I have the 3.42's. I just have an RPO for it. That 3.73 option must have been pretty rare.

 

I've got a 94 6 speed sitting in front of the house right now and they ALL came with 3.42's. 93 did not have 3.73's as an option either, but did have 3.23's stock due to that year the 6 speed didn't have such a low 6th gear.

 

My bad. The autos were the ones that came with the 3.23 optional from the 2.73

I used to sell these things back in '94-'95 in which '94 was the change over years from the '93.

Plus that was 10 yrs ago that I sold them.

I found this which should help.

Year Model/Optn 1st 2nd 3rd 4th 5th 6th Final
---- ------------- ---- ---- ---- ---- ---- ---- -----
1993 Manual/M28 3.36 2.07 1.35 1.00 0.80 0.62 2.73 (GU2)
1993 Manual/M29 2.97 2.07 1.43 1.00 0.80 0.62 3.23 (GU4)
1993 Auto/MX0 3.06 1.63 1.00 0.70 -- -- 2.73 (GU2)
1993 Auto/MX0 3.06 1.63 1.00 0.70 -- -- 3.23 (GU5)

1994 Manual/MN6 2.66 1.78 1.30 1.00 0.74 0.50 3.42 (GU6)
1994 Auto/MX0 3.06 1.63 1.00 0.70 -- -- 2.73 (GU2)
1994 Auto/MX0 3.06 1.63 1.00 0.70 -- -- 3.23 (GU5)
The '95s and later have the same ratios as the '94s. Aside from the CAGS provision and different gearing/input shaft (on the post 93's), all of the 6-speed transmissions are basically the same.

There was a way to get the 3.73, and I'm pretty sure it was with the 1LE option.

 

is noise or vibration an issue with 3.73? I was advised to go 3.55 as that could be an issue. ever hear of that argument against 3.73?

 

I've heard that, but not because the gears were 3.73's.

The main reason is because of some manufactures. They concentrate on making the ring and pinion gear strong more than making them quiet.

Another problem is because of sloppy installation. If the backlash and depth of how much the gears mesh isn't done just right, there's usually excessive noise.

 

that, and your driveshaft is spinning that much faster.

i put an LS1 shaft on, with richmond 3.42's (they are not that loud, but he flowmasters may just drownd it out.) i can verify that it is silky smooth up to about 130.

 

3.42's felt good with all the setups I've had with this car.

305TBI, 350 TBI, and I am sure it'll do great with the TPI.