I 'm thinking about sitching my 2.73 gear for a 4.10 one . Would it be streetable?

 

That depends on:

1) your opinion of streetable
2) the type of driving you do (around town, freeway, etc...)
3) your rear tire size

In my opinion it would be streetable, others might disagree.

 

I run 28" tires, 700 trans and 4.10's. Streetable......yes. Daily driver-able........I wouldn't consider it to be.

My daily has 3.42's and a T5. I wouldn't go more than that.

 

Gas milage will probably suck, especially on the highway. Be fun to drive though.

 

I think you'll find, that's too much gear. Unless your motor is SUBSTANTIALLY non-stock, that gear will force the motor into a range of RPMs where it doesn't work very well. You'll have one of those cars with great grunt off the line, but won't be able to pass a semi on the highway.

About as far as you really need to go with a stock L03 is 3.42; or if yours is typically modified (headers & exhaust, cam, non-swirl-port heads, chip work), 3.73.

 

I went from 2.73s to 3.42s, loved it, 4.10s will be too much if its a DD, 3.42-3.73 will be the best for you

 

Thanks . And is there another car than third gen f-bodies that i could take the complete diff. (in a scrapyard) and stick it under the car?

 

I'm also undicided, I have 3.27 on a modifed 350 with 9bolt rear, I'm on the mid 12's and thinking about going with 4.10. I drive this car every day.

 

Bad choice then. Unless noise & fuel mileage are of no concern.

 

Do the math and look at the change in rpm at your normal highway speed. Then drive it in a gear that brings you close to that speed and equivalent rpm and see what it makes the engine do and the noise. LS1 guys say 4:10 with a T-56 and 3:73 with an auto....this is on the ls1 but reasons are the same. the T-56 has a .50 overdrive in 6th. I would not put a 4:10 in anything that was more than a weekend toy for strip or cruse. Also look at what others here know about going from a 2:73 to a 4:10, requires more change than just the gear set.

 

This is where you start having to make compromises. You're either going to lose ET with a 3.42 or lose street manners with a 4.10. That is why I waited to build my car until I bought another car for my daily driver. The decision is all up to you. The difference will be a few hundred RPM at the top end of the track, maybe 2 or 3 tenths.

 

I too recently went to 4.10's and love them. My motor is modified so I can take full advantage of the higher RPM operation but the street manners and the fuel mileage are not that bad. I have a T-5 and turn 2500 rpm at 70 mph. Not too bad considering the amount of acceleration I know have but I went from dismal 3.08's so I guess anything would be better!

 

Stay far away from highways.

 

Getting on is fun but that's about it!

 

Go with 3.42's and enjoy the change.

...And then go find another avatar. I had this one first.

 

sorry man... but it looks good.

 

i have 3.73's with a 305 TPI. they are great, the front end pops up real nicely and its quick off the line. they arent too bad on the highway...i would prefer to have 3.42's or maybe the next lowest, but the previous owner put them in. Your speedometer will be off unless u get a calibrator like i have. i would say 4.10's are too high and excessive for a street driven car.

 

I think he should get 3.73's. Remember he has a tbi setup and not a tpi. If it were a tpi car id say get 3.42's.

 

Thanks for the compliment, Mr. Plagarism.

 

I agree. The only reason I opted for the 4.10's over the 3.73's is the fact that my engine is built for higher RPM's. I make power well over the 5000rpm range so I can fully utilize the gearing. With the TBI I too would go with 3.73's.

 

Now, if you were to drive this car only on weekends and drive to the track, would it make sense to go with the 4.10s?

 

what most of the guys forgot to mention or OVERLOOKED is that the TRANSMISSION you use has a HUGE effect on what rear gear that will work correctly.
an OVERDRIVE transmission may make that 4.10:1 rear gear ratio almost ideal

example
a 700r4 has a 0.7 top gear ratio
a 4L80E has a 0.75 top gear ratio

http://users.erols.com/srweiss/calcmph.htm

http://users.erols.com/srweiss/calcrpm.htm

http://users.erols.com/srweiss/calcrgr.htm


lets assume you want to go thru the lights in the 1/4 mile at 130mph at 6500rpm, youve got 26.5" tires and a a 4L80E has a 0.75 top gear ratio..............use the calculators!! youll soon see a 4.11 rear is not STEEP enought
and that your cruise rpm is alot lower at 70mph than you might think in overdrive with that 4.11 rear gear

 

I daily drove my 94 TA with 4.10s just fine. Got about 20-22 highway mpg.

 

techically, a 4th gen would work, but it's a tad wider. Stick with 3rd gen rears.

I think more of the gutless v-6 cars had the steeper gears stock, so they might be a good bet to steal a rear from. but forget the posi.

 

4.10's on auto 700r4 is COMPLETELY useless and overkill. your not trappin over 5500rpms or higher.. so they are pointless. on a TPI 350 car, 3.73's had one guy shifting into overdrive before the end of the 1/4. his car has slp runners and ported base and he shifts at 5000rpms or so. 4.10's is absolutely tooo much. on the highway, in overdrive, 3.42's is all i would want. 3.73's only if your not TPI and have a power band that extends to if or over 5500rpms like a superram/miniram setup



and with a 26inch tall tire... i dont think they will have any speedo gears to work with 4.10's to make your speedo accurate. if you have a cable driven speedo that is.

 

Keep the 2.73's and just install a 3000 stall.

I almost went to 3.42's instead of a stall and it would have been a huge mistake.

 

Well it seems as if everyone here believes that the 4.10's are not streetable but I guess that depends on your definition of streetable. I read the response about having to shift into overdrive in the 1/4 but how does that apply to the street? I have a T-5 with the same gearing as a 700r4 and feel that my car is completely streetable. It all depends on the owners preference of RPM's at cruise.

 

Why can I put a 3.73 gear in my TBI engine but not in a TPI one?

 

Care to explain?

 

Pulled this from a site so i wouldn't have to type it all out.

2.73's with a 3000 stall > 3.73's with a 1800 stall{I think that's our stock stall speed}

The point of selecting a higher stall converter is to find one which stalls close to the peak power range of the engine. If an engine makes peak torque between 3000-3500 rpm, a converter which stalls at 3000 would give the car a much quicker acceleration and launch, compared to the same engine and a stock converter which started the car off at 1800 rpm. Therefore the stall speed of a converter is not only determined by its design, but also by the power band of the engine and camshaft.

Another way to look at this is to think of a manual transmission and clutch. At the race track you could rev the car to 3500 rpm and dump the clutch, and assuming the clutch did not slip the engine and driveline would couple and the car would launch hard. A torque converter offers the same advantage, but it is constant and not as hard on the driveline -how often can you dump the clutch on the street?

 

You don't put a big stall in a car instead of a set of gears

They both work together to keep the engine in it's powerband. You need the proper combination of converter, gear and tire size.

Are 4.10's streetable? Yes. Too much for a TPI car? Most likely. Would your car benefit from a converter? Yes. You need the proper cobination of all of these to get the most out of the car at the track. Since it spends most of it's life on the street as a daily instead of a race car you can afford to sacrifice ET and track performance. 3.73's and a 26-2800 stall lockup converter would get you close to your potential without sacrificing too much streetability.

FWIW, I shift my car at 5800 RPM ( peak power is at 5600 ), have a 3200 stall converter with 5% slippage, 4.10's and 28" MT's. The car goes through the traps at 5600 RPM and 111mph.

 

If you want any decent gas mileage you do.

I will admit that i would be faster with 3.23's or 3.42's but i'm more then happy with how the car perform's with the 2.73's.

When i goto a moser i probably will step up to 3.42's.

 

High stall converters hurt your mileage too.

 

One of the reasons why i have 2.73's.

What does your car average mileage wise dialed?

 

Who knows. I don't drive it every day. Around 12 if I don't go to the track and beat on it. If I go to the track I burn 1/3 of a tank driving 20 miles each way and making 4 or 5 passes.

 

Dialed_In what is your 60' and ET?

Thanks

 

Dunno.Tracks closed before I got a good set of tires. It trapped 112 MPH on the street tires with a 2.6 60' . Since then I got some Mickey's and a new converter so we'll see in the Spring if I can get my trans built by then.

 

yeah but why the gear would differ from a tbi to a tpi?

 

A tbi can be geared higher than a tpi car. TPI cars respond better to mild gearing beacuse gears such as 3.23,3.27, and 3.42's keep it right in its power band. If you put 3.73's or 4.11's in a tpi car it is possible that you will be shifting into overdrive before the end of the 1/4 mile. TPI cars do not like to be reved high beacuse they make all of there power down low. So id say for a tbi with a 5-speed go with 3.73's.

 

I've got a 700r4. Is a 3.42 better?

 

a 3000 stall with 2.73's would be terrible for the street. You would be putting a huge load on teh torque converter all of the time becuase of stop and go traffic and driving through town. Im not sayings its a bad idea and with a TPI would probably work well at the strip, but i think that stall is to high for those gears on the street.

 

If i had a TPI i would agree with you. I'm running a carb setup with a crate 350 and i haven't ever had a problem.

It's also not really a daily driver. It's more of a spring/summer car.

 

ya with a carb and a crate motor it would prolly be ok. As long as it is mainly a toy, so that the torque converter is stressed out everyday with "normal" driving... not that us Third gen owners do much of that

 

The 3.42's would be better for highway driving. The 3.73's would be better for 1/4 racing. It depends on what you want.

 

thanks

 

It all depends on what you want to do with the car. If you are only after 1/4 mile times, with the powerband of the TPI I would say 3.73. 4.10's with 26" tires will have you at the redline in 3rd gear about 200 yds before the finish line & on the fence about shifting into OD, if your trans is able. Cruising in OD with 4.11 isn't too bad, if dont mind the engine spinning around 2200 or so @ 60 mph, but at 5500 you be just over 100mph & out of breath. Also the 1-2 shift under light throttle is about 7 mph & seems almost like it's like it starts out in 2nd. I beleive the best overall gear for TPI or TBI is 3.42, that would make the most out of you powerband & give decent steet manners. Also a quality (tight) converter like an Edge or Vigilante would do wonders with a 3.42 gear.

 

I'm currently doing 100mph @ 3000rpm with 3.23 and spicy tranny. Is that good, bad or average? Will soon be installing a 12 bolt Strange with 3.42 gears. I will post the changes after install is done.

 

dang this is funny to hear you guys goin whoa 2000 at 70 is a lot geeze my car runs 3000 in OD at 70.

 

Can I find GM's 3.42 posi diff in a junkyard?

 

Im pretty sure you have the 10-bolt. So yes they should be easy to find in a junk yard.