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Hey Guys, 

I am getting to the point where I need to choose the right Transmission.  

I'm swapping in an LS1 into my 1974 260Z.

Question is; Is there a specific year, or vehicle that is best to pull a used T56 from?

I know they have different gear ratios, and also different dimension for the gear lever placement.

Is there one that fits perfectly without having to adjust the placement of the gear lever?

I will be doing open track days, and just some weekend driving.  So acceleration is important to me, not so much top speed.

I hope that helps!

Thanks!

-Jack

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The 98-2002 Camarillo/Firebird is your best bet. The GTO tranny fits equally as well but you need a $30 part (offset lever) to convert the shifter. The GTO trans is stronger and has a lower 1st and second gears (lower than optimal) than the Camaro version. Also, the Camaro version is better supported by repair vendors like Liberty or RSM for modifications like dog rings and face plating. Probably the best new tranny is gonna be a brand new T56 Magnum but the tail housing has to be switched to the Camaro tail housing to put the shifter in proper location, which is something Liberty can do for a fee. You probably don't need 6th gear-a 5 speed is probably adequate. Go to Tremec's site and you can see the different gear ratio options available in the T56 magnum. I'd pick one with the smallest numbers for gears 1 & 2, and the largest gears for 5 & 6 (you don't need a .5 6th ratio for a road course car. I bet gears 3 & 4 are the same for all of them.

Edited by RebekahsZ

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The 98-2002 Camarillo/Firebird is your best bet. The GTO tranny fits equally as well but you need a $30 part (offset lever) to convert the shifter. The GTO trans is stronger and has a lower 1st and second gears (lower than optimal) than the Camaro version. Also, the Camaro version is better supported by repair vendors like Liberty or RSM for modifications like dog rings and face plating. Probably the best new tranny is gonna be a brand new T56 Magnum but the tail housing has to be switched to the Camaro tail housing to put the shifter in proper location, which is something Liberty can do for a fee. You probably don't need 6th gear-a 5 speed is probably adequate. Go to Tremec's site and you can see the different gear ratio options available in the T56 magnum. I'd pick one with the smallest numbers for gears 1 & 2, and the largest gears for 5 & 6 (you don't need a .5 6th ratio for a road course car. I bet gears 3 & 4 are the same for all of them.

The standard offering from Tremec for the Magnum is a wide ratio and a narrow ratio gearset

wide ratio:

2.97

2.10

1.46

1.00

0.74

0.50

 

Narrow ratio:

2.66

1,78

1.30

1.00

0.80

0.63

 

That said - Liberty can mix and match ratios (at least for the overdrives) for a fee.

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If road racing, I'd get the 2.66 version. I'm getting the 2.97 version for the .75 5th gear for landspeed. I probably won't have the power to pull anything lower, like the .63 or .5. It would be cool for me to have a .86 5th and a .75 6th, but I don't think they can do it that way. I guess with shorter tires I might be able to use the .63 but the .5 is just dead weight. Of note: the T56 uses a 26 spline output shaft and the Magnum uses a 31 spline output shaft, so upgrading means ya gotta buy a new slip yoke. It's tough to have a car that is best at everything. Best bet is to pick something and get to the track!

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I used an 04 GTO as a donor.  I had to redo the shifter and its mounting as stated above, other than that it appears to be fine.  It is in the car and other than a couple of ears being trimmed it fits in a Series 1 240.  I did swap the output yoke when I had the driveshaft made, the GTO used the rubber donut and now it has a regular U joint on both ends.  HTH, Richard. 

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Get a 2.66 1st gear unit. These cars are light enough you don't need the extra motivation to get them going.

 

F Body trans is good in stock form, can hold good power (700+) with a few drop in parts

 

T56 Magnum is great, with larger holding capacity.

 

As Keith stated, stay away from the CTSV unit as they have a CV output rather than a slip yoke, making the connection a bit more difficult.

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Wow. Intense build. This will be fun to follow...... I'm using the 6speed out of a 98 SSZ28 with 3:90 R200 LSD and it works great for me.

How's that 3:90 on the street? I just bought a 3:70 and I'm worried about 1st gear being unusable with a T56 and high fwy revs at cruise.

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Posted (edited)

If starting from scratch I would not do a T56. I had a complete f-body donor so went that way but for competition it really sucks. It's very heavy, shifts slow and clunky, 5th gear is way too low and 6th is unusable. Really expensive to rebuild. If you have access to a cheap functional one they fit easy, shifter lines up perfect, and are pretty durable. This is my opinion after competing with one for 9 years now.

 

3.90 will get you going if you already have it but is too high IME. Also depends on your tire diameter though. 3.7 vs 3.54 or otherwise is going to depend again in tire diameter and the track you run.

Edited by heavy85

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3:90 works great for me and is very usable for AutoX...... I had a 3:70 that was a little better across the board but I trashed the ring and pinon... swapped in a spare 3:90 I had into the LSD pumpkin and I'm happy with it.  If you're a drag guy 1st is worthless but its fine for street driving.  6th is sort of an overdrive but honestly is "usable" as the car still pulls hard.  My home track in Thunderhill, 3-4-5 are all thats really needed with my set up.  Jim 

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If starting from scratch I would not do a T56. I had a complete f-body donor so went that way but for competition it really sucks. It's very heavy, shifts slow and clunky, 5th gear is way too low and 6th is unusable. Really expensive to rebuild. If you have access to a cheap functional one they fit easy, shifter lines up perfect, and are pretty durable. This is my opinion after competing with one for 9 years now.

3.90 will get you going if you already have it but is too high IME. Also depends on your tire diameter though. 3.7 vs 3.54 or otherwise is going to depend again in tire diameter and the track you run.

What manual trans would you use? I've thought about the 350-370Z trans with adapter but with mixed reviews on durability behind a LS motors torque. Even considered a G Force T5.

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The CD009 tranny from the 350Z is good to go and shifts really slick. I've never had one behind and LS but my previous 350Z with 12 pounds of boost put down solid hp and tq and with was smooth as butter. The T56 is a bit "chunky" but very solid and gates easy into desired gear for me with a short throw shifter. My 02. Jim

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The CD009 tranny from the 350Z is good to go and shifts really slick. I've never had one behind and LS but my previous 350Z with 12 pounds of boost put down solid hp and tq and with was smooth as butter. The T56 is a bit "chunky" but very solid and gates easy into desired gear for me with a short throw shifter. My 02. Jim

I've heard good and bad about them. They are definitely cheaper than a T56 even bought new. I'm curious about shifter placement and torque holding capacity.

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What manual trans would you use? I've thought about the 350-370Z trans with adapter but with mixed reviews on durability behind a LS motors torque. Even considered a G Force T5.

Therein lies the problem. If I had the time and wanted to spend the money I would sell mine and go to 5 speed of some sort but I never got that far. First and foremost need to decide what you are going to do with it. If just have fun but not compete then it's a great option but then when you want to get to the pointy end then it's not the droid you are looking for. FYI I just had mine rebuilt and was $2400 which could have bought a nice new 5 speed. I just didn't have the time to research and modify everything to make the change so at least for now have kept the T56.

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