Which T56?
Thread Starter
Instructor
Joined: Dec 2009
Posts: 221
Likes: 28
From: Bakersfield CA
Which T56?
I have heard people say to get a large rear gear like 3.73 or 4.10 to go with the wide ratio T56, mainly due to the low .50 6th gear, otherwise the 6th is unusable. My question is doesn't that make the 1st gear virtually worthless 2.97x3.73= 11.07 or 2.97x4.10=12.1.
Isn't that too high compared to the magical 10 for 1st?
But if you go with a close ratio 1st gear for me would be 2.66x3.36=8.9 but the 6th gear is about where I want, 76mph at 2,000rpm on stock 27" tire
I have a 3.36 rear gear and am trying to figure which tranny to go with...
Seems like neither of the T56's are set up ideally. I love the set up I have in the 04 z06 but that tranny's cogs aren't offered aftermarket
Suggestions?
Please enlighten me
Isn't that too high compared to the magical 10 for 1st?
But if you go with a close ratio 1st gear for me would be 2.66x3.36=8.9 but the 6th gear is about where I want, 76mph at 2,000rpm on stock 27" tire
I have a 3.36 rear gear and am trying to figure which tranny to go with...
Seems like neither of the T56's are set up ideally. I love the set up I have in the 04 z06 but that tranny's cogs aren't offered aftermarket
Suggestions?
Please enlighten me
Last edited by dave1234; Dec 21, 2014 at 07:30 PM.
Race Director
Joined: Dec 1999
Posts: 19,610
Likes: 778
From: Forked River NJ
I am running an 06 GTO a T56. I run a 3.70 rear. 1st gear is as I recall 2.97 and 6th is a .62. This combo works about as well as any combo. I don't buy into the magical 10ish 1st gear ratio. I have run this setup behind a 383 with about 500 HP. Currently running it behind and Ls3 with a little over 500 HP.
Melting Slicks
Joined: Jun 2011
Posts: 3,116
Likes: 598
I have heard people say to get large rear gear like 3.73 or 4.10 to go with the wide ratio T56 mainly due to the low .50 6th gear, otherwise the 6th is unusable. My question is doesn't that make the 1st gear virtually worthless 2.97x3.73= 11.07 or 2.97x4.10=12.1.
Isn't that too high compared to the magical 10 for 1st?
But if you go with a close ratio 1st gear for me would be 2.66x3.36=8.9 but the 6th gear is about where I want, 76mph at 2,000rpm on stock 27" tire
I have a 3.36 rear gear and am trying to figure which tranny to go with...
Seems like neither of the T56's are set up ideally. I love the set up I have in the 04 z06 but that tranny's cogs aren't offered aftermarket
Suggestions?
Please enlighten me
Isn't that too high compared to the magical 10 for 1st?
But if you go with a close ratio 1st gear for me would be 2.66x3.36=8.9 but the 6th gear is about where I want, 76mph at 2,000rpm on stock 27" tire
I have a 3.36 rear gear and am trying to figure which tranny to go with...
Seems like neither of the T56's are set up ideally. I love the set up I have in the 04 z06 but that tranny's cogs aren't offered aftermarket
Suggestions?
Please enlighten me
2.97:1
2.07:1
1.43:1
1.00:1
0.84:1
0.56:1
This compared to a 3:36 rear with the T56 gears in a blind test you would not be able to notice a difference.
If you are road racing / Drag racing then pick a ratio that works with the rpm / hp / torque curve of the engine.
For street driving you will not notice any difference.
Burning Brakes
Joined: Oct 2008
Posts: 1,037
Likes: 14
From: Mobile Alabama
It also depends on the torque range range of your engine. I use the .57 6th gear (TR6060) with a 3:55 rear and a injected LS with only ~300HP. I don't think it would be usable with a carbed SBC of the same power -or even a little more because the torque curve would not allow it to run well at that low a RPM. Even then I only use 6th above 60mph and run ~1500rpm @75
Thread Starter
Instructor
Joined: Dec 2009
Posts: 221
Likes: 28
From: Bakersfield CA
LS1/MM6 T56 2.66, 1.78, 1.30, 1.00, 0.74, 0.50 seems geared for lower rpms
LS6/M12 T56 2.97, 2.07, 1.43, 1.00, 0.84, 0.56 seems geared for rpms
Aftermarket T56's:
Close T56 2.66, 1.78, 1.30, 1.00, 0.80, 0.63
Im worried with this I would want a 3.73 axle to get any acceleration instead of the 3.36 I have, but that I would be getting too many rpms in 6th to be useful
Wide T56 2.97, 2.10, 1.46, 1.00, 0.74, 0.50
Im thinking with my 3.36 axle, the first gear in this would be nice but as others have said you would have to hit crazy speed to be able to actually use 6th (80+mph)
It seems like Im noticing that the wide is reallyyy wide considering 1st and 6th.
For aftermarket I would like the 2.97 1st from wide ratio and the .63 6th from close ratio.
Who knows. Maybe you cant have it all
LS6/M12 T56 2.97, 2.07, 1.43, 1.00, 0.84, 0.56 seems geared for rpms
Aftermarket T56's:
Close T56 2.66, 1.78, 1.30, 1.00, 0.80, 0.63
Im worried with this I would want a 3.73 axle to get any acceleration instead of the 3.36 I have, but that I would be getting too many rpms in 6th to be useful
Wide T56 2.97, 2.10, 1.46, 1.00, 0.74, 0.50
Im thinking with my 3.36 axle, the first gear in this would be nice but as others have said you would have to hit crazy speed to be able to actually use 6th (80+mph)
It seems like Im noticing that the wide is reallyyy wide considering 1st and 6th.
For aftermarket I would like the 2.97 1st from wide ratio and the .63 6th from close ratio.
Who knows. Maybe you cant have it all
Last edited by dave1234; Dec 21, 2014 at 08:20 PM.
Drifting
Joined: May 2005
Posts: 1,968
Likes: 44
From: East TN
My T56 is out of a 94' Trans Am with 2.66, 1.78, 1.30, 1.00, .74, .50 and I use a 3.70 rear with 25.55" tires (275/40 ZR17). I use 5th gear on highways and 6th gear on the interstates. At about 65mph in 5th I'm at about 2450 rpm, and in 6th I'm at about 1650.
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,063
From: altered state
St. Jude Donor '05
I have in the 04 z06 but that tranny's cogs aren't offered aftermarket
6th is just for mpg and not pulling in these things;dont buy the 10:1 1st is the only way either moreso a general guide.
Race Director
Joined: May 2005
Posts: 10,674
Likes: 122
From: Millington Illinois
St. Jude Donor '08-'09
LS1/MM6 T56 2.66, 1.78, 1.30, 1.00, 0.74, 0.50 seems geared for lower rpms
LS6/M12 T56 2.97, 2.07, 1.43, 1.00, 0.84, 0.56 seems geared for rpms
Aftermarket T56's:
Close T56 2.66, 1.78, 1.30, 1.00, 0.80, 0.63
Im worried with this I would want a 3.73 axle to get any acceleration instead of the 3.36 I have, but that I would be getting too many rpms in 6th to be useful
Wide T56 2.97, 2.10, 1.46, 1.00, 0.74, 0.50
Im thinking with my 3.36 axle, the first gear in this would be nice but as others have said you would have to hit crazy speed to be able to actually use 6th (80+mph)
It seems like Im noticing that the wide is reallyyy wide considering 1st and 6th.
For aftermarket I would like the 2.97 1st from wide ratio and the .63 6th from close ratio.
Who knows. Maybe you cant have it all
LS6/M12 T56 2.97, 2.07, 1.43, 1.00, 0.84, 0.56 seems geared for rpms
Aftermarket T56's:
Close T56 2.66, 1.78, 1.30, 1.00, 0.80, 0.63
Im worried with this I would want a 3.73 axle to get any acceleration instead of the 3.36 I have, but that I would be getting too many rpms in 6th to be useful
Wide T56 2.97, 2.10, 1.46, 1.00, 0.74, 0.50
Im thinking with my 3.36 axle, the first gear in this would be nice but as others have said you would have to hit crazy speed to be able to actually use 6th (80+mph)
It seems like Im noticing that the wide is reallyyy wide considering 1st and 6th.
For aftermarket I would like the 2.97 1st from wide ratio and the .63 6th from close ratio.
Who knows. Maybe you cant have it all
10.93 to 1 overall first gear- 47 MPH @ Redline,
3.28 to 1 fifth gear- 2700 RPM @ 65 MPH
2.58 to 1 sixth gear- 2100 RPM @ 65 MPH - 2600 RPM @ 80 MPH.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski