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Old 06-01-2008, 07:19 PM   #1
chevjayfsd
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3.73 or 4.11??

Hey guys,

We are going to get some new gears + posi. Right now we have 3.08 and no posi, and they are just dogs... My question though is should we go for 373s or 411s? It will see absolutely no highway driving, so that is not a concern, tranny is a th350...
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Old 06-01-2008, 07:25 PM   #2
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Re: 3.73 or 4.11??

If you're absolutely sure that you won't ever use it on the highway, then I'd go 4.11's!! Otherwise, I'd go 3.73 for that occasional long distance trip.
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Old 06-01-2008, 07:27 PM   #3
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Re: 3.73 or 4.11??

have to agree, gears make all the difference. if theres no highway, GO HIGHER

4.56!!
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Old 06-01-2008, 07:42 PM   #4
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Re: 3.73 or 4.11??

Ah.....that's lower
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Old 06-01-2008, 08:27 PM   #5
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Re: 3.73 or 4.11??

It depends on what kind of performance you want, also tire size can affect things.

I am running 3.73 gears with 31's, for my kind of driving it works out great. Most of my driving is in town and country roads.

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Old 06-01-2008, 08:38 PM   #6
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Re: 3.73 or 4.11??

I think you would like 3.55 with that turbo350 no overdrive, but thats my opinion.

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Old 06-01-2008, 10:23 PM   #7
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Re: 3.73 or 4.11??

No highway 4.56 its fun.
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Old 06-01-2008, 10:29 PM   #8
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Re: 3.73 or 4.11??

I've got 4.11's, posi and a very warm 350 and up to about 40 I have very limited traction with 30 inch tires that are 285's.
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Old 06-01-2008, 10:42 PM   #9
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Re: 3.73 or 4.11??

Quote:
Originally Posted by Gulf Rat View Post
I think you would like 3.55 with that turbo350 no overdrive, but thats my opinion.

Gulf Rat
I have 3.08 Posi on "Merlot" and I found a 3.42 on Evil Bay. I was going with
a 3.55 or 3.73 but with "GQ's" motor & a 700R I think I'll be happy with it

If it will NEVER see the highway then go MPG is gonna suck anyways.
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Old 06-01-2008, 10:50 PM   #10
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Re: 3.73 or 4.11??

Tires are 275/60's = 28" tall... If your getting no traction with 30" tires... than what would that do with 28"!!! hahaa
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Old 06-01-2008, 11:27 PM   #11
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Re: 3.73 or 4.11??

Quote:
Originally Posted by LUV2XCLR8 View Post
I have 3.08 Posi on "Merlot" and I found a 3.42 on Evil Bay. I was going with
a 3.55 or 3.73 but with "GQ's" motor & a 700R I think I'll be happy with it

If it will NEVER see the highway then go MPG is gonna suck anyways.
3.73 with a 700R4 is great pick, me using 3.73 with late model truck 5 speed.

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Old 06-01-2008, 11:41 PM   #12
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Re: 3.73 or 4.11??

I like my 3.73's. It really picked the truck up from the 3.08s and I can still go down the freeway @65 at right around 3k rpms. Im running a 28" tire. I drive it to the track and cross the finish line at around 4200rpms (1/4 mile) It would pick up a couple tenths with a lower (higher numerically) gear but driving the freeway would suck (gas that is). So my vote with no freeway driving would be the 4.11's Those would be a fun gear
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Old 06-02-2008, 01:23 AM   #13
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Re: 3.73 or 4.11??

Quote:
Originally Posted by Gulf Rat View Post
3.73 with a 700R4 is great pick, me using 3.73 with late model truck 5 speed.

Gulf Rat
Agreed, but we opted for the 3.42 since the "GQ" motor is going in front
of it. That way I can drive it long distances and get ok MPG. (Right now
in the 4wd w/ 3.08's and a 350 auto I only get 8, yes only 8 MPG)
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Old 06-02-2008, 04:43 AM   #14
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Re: 3.73 or 4.11??

I'm get 19 mpg if I drive 70mph, with a 350 mild cam Quadjet, no headers, daul exh. 3.73 gear.
Not bad for old 71 Chevy..

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Old 06-02-2008, 08:08 AM   #15
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Re: 3.73 or 4.11??

3:73 is about perfect with your tire combination.What motor are you running,and what are your cam specs.Too much gear with not enough cam and you'll be running out of motor.I had a 4:56 gear years ago and it was fun for about two weeks.Went back to 3:73s and never regretted it.Just my .02
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Old 06-02-2008, 03:19 PM   #16
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Re: 3.73 or 4.11??

You're looking at a new rear axle, if Im not mistaken 4.11's won't fit in a pumkin that 3.07's came stock in. Pumpkin is too small-
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Old 06-02-2008, 03:22 PM   #17
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Re: 3.73 or 4.11??

Quote:
Originally Posted by Gulf Rat View Post
I'm get 19 mpg if I drive 70mph, with a 350 mild cam Quadjet, no headers, daul exh. 3.73 gear.
Not bad for old 71 Chevy..

Gulf Rat
ARE YOU SERIOUS??? What's your secret? I get about 13mpg w/ a built 350 and 3.07's!!! Ahh...but Im running a TH350. Do you have a 4 or 5 speed tranny?
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Old 06-02-2008, 06:31 PM   #18
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Re: 3.73 or 4.11??

WOW 19 out of a carbed 350 HOW????
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Old 06-02-2008, 07:24 PM   #19
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Re: 3.73 or 4.11??

Quote:
You're looking at a new rear axle, if Im not mistaken 4.11's won't fit in a pumkin that 3.07's came stock in. Pumpkin is too small-
It is not the entire axle housing that is different, just the "carrier". The part that the ring gear bolts onto. The difference is in the off-set of the flange. "High" gears (lower numerically) have more teeth on the pinion, making it larger in diameter. This forces the ring to be further off center.
Gear manifacturers compensate for this as the ratio gets lower. They make the ring gear thicker to match the smaller pinion, but only so far. Then you have to have a "low ratio" carrier, which has the ring flange closer to center.
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Old 06-03-2008, 02:21 PM   #20
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Wink Re: 3.73 or 4.11??

Quote:
Originally Posted by shortbed70 View Post
WOW 19 out of a carbed 350 HOW????
I call Especially at 70mph.
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Old 06-03-2008, 04:46 PM   #21
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Re: 3.73 or 4.11??

Quote:
Originally Posted by OrangeCrush1970 View Post
ARE YOU SERIOUS??? What's your secret? I get about 13mpg w/ a built 350 and 3.07's!!! Ahh...but Im running a TH350. Do you have a 4 or 5 speed tranny?
Secret, no real secret...5 speed trany, 275/60-17 tire thats 31" tall and keep your foot out of the 4b. Quadrejet's have always got me good gas mileage. Having the right combo of carb,cam,gearing is the secret. BTW that highway mileage, city around 15.

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Old 06-07-2008, 01:10 AM   #22
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Re: 3.73 or 4.11??

i have 373 with 295/50/15 with a saginaw 4 spd and a pretty warm motor but with what i have in the rear (gears and tires) what would it make my gears?
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Old 06-07-2008, 02:16 AM   #23
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Re: 3.73 or 4.11??

Quote:
Originally Posted by Gulf Rat View Post
Secret, no real secret...5 speed trany, 275/60-17 tire thats 31" tall and keep your foot out of the 4b. Quadrejet's have always got me good gas mileage. Having the right combo of carb,cam,gearing is the secret. BTW that highway mileage, city around 15.

Gulf Rat
Just curious, have you had your speedo calibrated?
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Old 06-07-2008, 02:31 AM   #24
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Re: 3.73 or 4.11??

Quote:
Originally Posted by LUV2XCLR8 View Post
Agreed, but we opted for the 3.42 since the "GQ" motor is going in front
of it. That way I can drive it long distances and get ok MPG. (Right now
in the 4wd w/ 3.08's and a 350 auto I only get 8, yes only 8 MPG)

This is just what I have in LowBuck and love it. The lower 1st gear in the 700R4 gives you that 3.73 take off feel and the 27% OD gives that 3.08 cruise. At 70MPH I run right about 2000 RPM and that is perfect for the vett LT1. It is one of the most versatile truck combo's I have ever had and I have had alot

Kevin
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Old 06-07-2008, 10:01 AM   #25
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Re: 3.73 or 4.11??

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Just curious, have you had your speedo calibrated?
Yep, changed the gear on the speedo cable checked it with GPS...would you like to come down and check the gas mileage yourself, come on down i'll have a cold one waiting.

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