make sure you get the thick gear made for the 3-series carrier
4.11 gears
Race Director
Joined: Jan 2003
Posts: 15,175
Likes: 86
From: State of Confusion
I was also told that ZIP Products makes either 3.90 or 4.11 (maybe both ?) that is capatable with the OEM carrier, but when they didn't retrun my e-mail requesting further info, I settled for 3.73s
Burning Brakes
Joined: Feb 2005
Posts: 1,235
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From: Mesa AZ
Safety Car
Joined: Oct 2004
Posts: 3,923
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From: Youngstown Ohio
Race Director
Joined: Jan 2003
Posts: 15,175
Likes: 86
From: State of Confusion
I believe the above link is for the '63-'79 Corvette IRS, but the '80-up C3s, such as the Original Poster's, uses a Dana-44 rear-end, and I'm not-sure anybody makes a thick-geared set for those carriers.
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Drifting
Joined: Aug 2003
Posts: 1,424
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From: Lakeland FL
This is the correct link for the 4.11's from Zip for your '82 diff: http://www.zip-products.com/Zip/prod...ED64B868D756EE
Now if you're considering a 5-speed conversion, Gene over at Keisler convinced me that the 3.73's along with the TKO-500 would have my '81 launching like it has 4.11's in it when compared to the original stuff. I don't know how that calculation was determined but I assume it is because the gearing in the tranny is also different.
Now if you're considering a 5-speed conversion, Gene over at Keisler convinced me that the 3.73's along with the TKO-500 would have my '81 launching like it has 4.11's in it when compared to the original stuff. I don't know how that calculation was determined but I assume it is because the gearing in the tranny is also different.
Safety Car
Joined: Oct 2004
Posts: 3,923
Likes: 733
From: Youngstown Ohio
This is the correct link for the 4.11's from Zip for your '82 diff: http://www.zip-products.com/Zip/prod...ED64B868D756EE
Now if you're considering a 5-speed conversion, Gene over at Keisler convinced me that the 3.73's along with the TKO-500 would have my '81 launching like it has 4.11's in it when compared to the original stuff. I don't know how that calculation was determined but I assume it is because the gearing in the tranny is also different.
Now if you're considering a 5-speed conversion, Gene over at Keisler convinced me that the 3.73's along with the TKO-500 would have my '81 launching like it has 4.11's in it when compared to the original stuff. I don't know how that calculation was determined but I assume it is because the gearing in the tranny is also different.
Instructor
Joined: Mar 2004
Posts: 127
Likes: 0
From: Houston TX
I'm sure one of our resident differential gurus will chime in any moment, but also take a look or call tomsdifferentials.com.
These guys have some of the best hardware available and are great to deal with. I just got all my diff internals from them and also run their spindles.
One quote on their web sites states:
When changing ratios of 2.72-3.73 to gear ratios of 3.92-5.89, the posi case or carrier unit must be changed.
See how lucky I am with my 77? Theoretically I could run a 4.56 using my 3-carrier
(I went with the 3.73, though, as I have a 0.64 OD tranny)
Good luck !
Michael.
These guys have some of the best hardware available and are great to deal with. I just got all my diff internals from them and also run their spindles.
One quote on their web sites states:
When changing ratios of 2.72-3.73 to gear ratios of 3.92-5.89, the posi case or carrier unit must be changed.
See how lucky I am with my 77? Theoretically I could run a 4.56 using my 3-carrier
(I went with the 3.73, though, as I have a 0.64 OD tranny)Good luck !
Michael.
Race Director
Joined: Jan 2003
Posts: 15,175
Likes: 86
From: State of Confusion
This is the correct link for the 4.11's from Zip for your '82 diff: http://www.zip-products.com/Zip/prod...ED64B868D756EE
Now if you're considering a 5-speed conversion, Gene over at Keisler convinced me that the 3.73's along with the TKO-500 would have my '81 launching like it has 4.11's in it when compared to the original stuff. I don't know how that calculation was determined but I assume it is because the gearing in the tranny is also different.
Now if you're considering a 5-speed conversion, Gene over at Keisler convinced me that the 3.73's along with the TKO-500 would have my '81 launching like it has 4.11's in it when compared to the original stuff. I don't know how that calculation was determined but I assume it is because the gearing in the tranny is also different.
Because I wanted my Z28 to move as-quickly-as possible off the line (for lightning-quick Reaction Times) when I bracket-race it, I used extra-low gear-set for the THM400, with a 2.75:1 First Gear, insetad of the OEM 2.48, with the 4.10 gears, which would let the car hit the Finish Line very-close to the RPM limit I wanted to use.
With the OEM gears and 4.10s, my 'Effective First Gear' was 10.168:1, but the 2.75:1 gear-set is 11.275 'Effective' gear-ratio:
11.275 div/by the OEM ratio of 2.48:1 makes the car 'feel' like it has 4.56 (really 4.546) gears off the line.
Thread Starter
Racer
Joined: Nov 2007
Posts: 367
Likes: 0
From: Las Vegas NV
This is the correct link for the 4.11's from Zip for your '82 diff: http://www.zip-products.com/Zip/prod...ED64B868D756EE
Now if you're considering a 5-speed conversion, Gene over at Keisler convinced me that the 3.73's along with the TKO-500 would have my '81 launching like it has 4.11's in it when compared to the original stuff. I don't know how that calculation was determined but I assume it is because the gearing in the tranny is also different.
Now if you're considering a 5-speed conversion, Gene over at Keisler convinced me that the 3.73's along with the TKO-500 would have my '81 launching like it has 4.11's in it when compared to the original stuff. I don't know how that calculation was determined but I assume it is because the gearing in the tranny is also different.
thanks for the help guys i think the 5 speed and 3.73s are in my future
