4.11 rear gears
Thread Starter
Team Owner
Joined: Nov 2004
Posts: 20,715
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From: Sorrento Italy
4.11 rear gears
hi, what's the main advantage of using a 4.11 rear gear on my '77 C3 (406ci 570hp 530tq)? and eventually what the disadvanges i might find? i'm rebuilding and uprating the rear axle (van steel) with this gear ratio, i have a 4 speeds t-10 stock but upgraded clutch/disk/etc...
thanks/Giu
thanks/Giu
Melting Slicks
Joined: May 2005
Posts: 2,152
Likes: 33
From: Folsom Ca
The main advantage I can think of over stock would be better off the line acceleration.
The main disadvantage would be higher RPMs especially noticable on the freeway if you ever take it on there.You`ll be over 3500RPM at 70MPH.
By comparison I have 700 tranny and in 4th at 70MPH my Vette is barely hitting 18-1900RPM with a 3.07 rear gear.Ofcourse I sacrafice off the line performance.
So you`ll also be using more gas if thats a concern for you.Your engine will be working harder and may not last as long if its always beiing revved high..
The main disadvantage would be higher RPMs especially noticable on the freeway if you ever take it on there.You`ll be over 3500RPM at 70MPH.
By comparison I have 700 tranny and in 4th at 70MPH my Vette is barely hitting 18-1900RPM with a 3.07 rear gear.Ofcourse I sacrafice off the line performance.
So you`ll also be using more gas if thats a concern for you.Your engine will be working harder and may not last as long if its always beiing revved high..
Thread Starter
Team Owner
Joined: Nov 2004
Posts: 20,715
Likes: 25
From: Sorrento Italy
thanks for the infos, i barely use highway and gas consumption is not an iusse as i use the vette only on dry week ends, the main iussue for me is to get the best performance on 0 to 60mph, i'll also fix a hurst comp shifter to allow quicker gear changes..
Melting Slicks
Joined: May 2005
Posts: 2,152
Likes: 33
From: Folsom Ca
Its all good then.4.11`s are your ticket.
I myself have considered changing to 3.55`s or 3.73 in the near future.I dont due much highway driving unless were on a Corvette run..once or twice a year.Plus that overdrive gear kinda makes up for it.
I myself have considered changing to 3.55`s or 3.73 in the near future.I dont due much highway driving unless were on a Corvette run..once or twice a year.Plus that overdrive gear kinda makes up for it.
Race Director
Joined: Nov 2000
Posts: 11,872
Likes: 12
From: Waterloo ontario Canada
Originally Posted by panic
thanks for the infos, i barely use highway and gas consumption is not an iusse as i use the vette only on dry week ends, the main iussue for me is to get the best performance on 0 to 60mph, i'll also fix a hurst comp shifter to allow quicker gear changes..
Without overdrive I wouldn't do it. Buzzing your engine in the 4000 plus range all the time causes excess wear, heat and noise.
Combined with overdrive and it's steep 1st gear again it is too much gearing in first but makes cruising bareable.
I wouldn't go over 3.55 without overdrive.
Race Director
Joined: Nov 2000
Posts: 11,872
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From: Waterloo ontario Canada
Originally Posted by L-82kid
If you don't use the highway or care about gas, why not try 4:56 gears.
I have had 3.08, 355, 373, 411 and 456 and recommend nothing more then 355 on the street without overdrive and found 411 with overdrive tolerable on the open road but NOT off the line.
Racer
Joined: Apr 2005
Posts: 494
Likes: 0
From: Virginia
Originally Posted by L-82kid
If you don't use the highway or care about gas, why not try 4:56 gears.
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Le Mans Master
Joined: Jan 2006
Posts: 6,506
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From: Butler Pa
I ran 4.56's with a smallblock for the first 10 years I had my car. Gas was relatively cheap and I never took it farther than 30 miles from home. I then switched to a 3.55 (still have the complete 4.56 rearend sitting in the garage) and lost some serious performance. If I had overdrive I would certainly put the 4.56's back in. A .76 OD would with 4.56 would act like a 3.45 rear gear.
Le Mans Master
Joined: Oct 2001
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From: Pine Bluff Arkansas
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15-'16-'17-'18-‘19-'20-'21
I love low gears. More go for your money. I think 4:11's would be perfect for you. I had 4:56's in a 69 Z. Just don't plan on making any long trips. Larry
Thread Starter
Team Owner
Joined: Nov 2004
Posts: 20,715
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From: Sorrento Italy
tks for the advices, my 4.11 in on the way, the rear axle will be uprated too and i've got hoosier strip tires waiting for the new set...is there a calculator that gives me the 0/60 or quarter times with 4.11 rear? thanks/Giu
Le Mans Master
Joined: Apr 2006
Posts: 5,403
Likes: 95
Stay with the 4.11 plan I too have driven a car on the street with
4.88s and couple friends had 5.13s. if you want to drive the car very
short distances at 50 miles an hour you could live with 4.56, but there
is a real change in driving between a 4.11 and a 4.56. I had 4.11s
in my 66 with an M/20 big block and loved it. but unless you
have one of these new fangled overdrives stay away from a 4.56.
4.88s and couple friends had 5.13s. if you want to drive the car very
short distances at 50 miles an hour you could live with 4.56, but there
is a real change in driving between a 4.11 and a 4.56. I had 4.11s
in my 66 with an M/20 big block and loved it. but unless you
have one of these new fangled overdrives stay away from a 4.56.
Racer
Joined: Jul 2004
Posts: 420
Likes: 1
From: Lapeer MI
I'm I the only one running 3.90 with a T400 tranny? I can't remember what I figured for the highway rpms but I thought it would be okay. Maybe I'll just cruise at 65mph.
Last edited by Red_Shift; May 2, 2006 at 08:03 PM.
Racer
Joined: Aug 2002
Posts: 289
Likes: 0
From: Albuquerque NM
Choice is the key and what you are willing to live with....Mine came with a 3:70 and M22. I love it! Ive driven the car cross country a few times (NM to NY) and drove it back and forth to work daily (years ago), part of the trip was Highway. As far as Fuel Economy well lets just say GPM (Grins Per Mile) was good
With good tires (27x10x15 Goodyear Slicks) you could blow away the 1/4 as fast as you can say Beat a Hemi!
Just go for it and have fun.
With good tires (27x10x15 Goodyear Slicks) you could blow away the 1/4 as fast as you can say Beat a Hemi! Just go for it and have fun.
Racer
Joined: Jul 2002
Posts: 275
Likes: 13
From: South Bend, Indiana
Originally Posted by lebvette
I love low gears. More go for your money. I think 4:11's would be perfect for you. I had 4:56's in a 69 Z. Just don't plan on making any long trips. Larry
I'm with you. I ran 4.11 with a TH400 on my '76 and wouldn't have it any other way. I had a C2 fuelie that came with 4.11 stock. I changed to 4.56 then later 4.88 GM gear and part number and had lots of fun. Bought those right over the counter at the Chevy dealer.
Thread Starter
Team Owner
Joined: Nov 2004
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From: Sorrento Italy
Originally Posted by torqvette
Panic, 570hp? Damn, what kind of heads and cam are you running? 
And everyone else, don't you need to change something other than the gears if you go higher than 4.11?
And everyone else, don't you need to change something other than the gears if you go higher than 4.11?
Thread Starter
Team Owner
Joined: Nov 2004
Posts: 20,715
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From: Sorrento Italy
Originally Posted by Jughead
Don't the 4.11's, and up, require a different carrier (diff case)?