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    Results 1 to 19 of 19
    1. #1
      Join Date
      Aug 2015
      Posts
      43
      Country Flag: United States

      Having a hard time deciding TKO 600 or T56 for my 69 mustang.

      I have a 69 mach that I am looking to do a manual trans swap on. Have the bulk of my funds just trying to scratch the rest together. Engine is a 392 Stroker 450hp/450lbs, hope to do head and cam swap in the next year or two which will put me 550 range. Rear gears is 3.89.

      Car will see aggressive street use, cruising, maybe an autocross event once I get all the final pieces of suspension done etc.

      Looking at Tko 600 with the Sure shift packages etc. offered by different companies or step up to the T56 and deal with the modding of my trans tunnel and the extra costs associated?

      I don't think I will over power the rating of either, my main worry is shifting. I want to be able to beat on it and shift reliably at 6500ish rpm maybe a touch more. This is a huge purchase for me as I have to do a lot of saving for that kinda $$, and wanna make sure I am happy and not get buyers remorse.

      Thanks in advance for the help.

    2. #2
      Join Date
      Oct 2014
      Location
      DFW, Texas
      Posts
      422
      Country Flag: United States
      T56 will be the last trans you buy. I found the TKO long-term reliability and high rpm limitations to be prohibitive. I wanted to bolt in a brand new trans and never [ever] look back.
      1972 Plymouth 'Cuda - Not LS-swapped, 5.7L Hemi [MS3 Gold Box], T56 Magnum 6-speed - 'Cuda Build Page
      1976 Dodge D100 - Warlock
      2016 Subaru WRX - E30 Tune

    3. #3
      Join Date
      Apr 2012
      Location
      Woodstock, IL
      Posts
      2,410
      Country Flag: United States
      <<<<<<< On the T56 bandwagon. Stick a better shifter in it from one of the trans companies (AP, SST, Bowler, Hurst) and never look back.

      -Dale
      SchwartzPerformance
      The leader in bolt-in muscle car chassis
      SchwartzPerformance.com | GMachineChassis.com | Facebook | Twitter | Instagram

      Dealer for: Forgeline, RideTech, Tremec, American Powertrain, Silver Sport Transmissions, GM Performance Parts, RECARO, Cerullo Seats, TMI Products, Vintage Air, Baer Brakes, Wilwood, BeCool, AFCO, Tanks Inc, Holley / Hooker, Ultimate Headers, Rick's Tanks, Moser Engineering, Currie, TechAFX, Stainless Works, II Much Fabrication, and many more

    4. #4
      Join Date
      Feb 2016
      Location
      Texas
      Posts
      93
      Country Flag: United States
      If you can swing it, go for the T56. I had to make this same decision and went with the Tremec Magnum (0.63 top gear). I did not like the jump in ratio from 4th to 5th with the TKO, whereas with the Magnum, I use 5th gear a lot around town. Go to any of the sources that provide an rpm vs mph calculator that takes into account your tire size and differential ratio. You can generate some curves to see what rpm you'll be running in the different gears for different mph. You can then easily see which trans will best suite your driving. In my case, my engine would be spinning more rpm than I wanted for a given mph, but too low if I were to shift into 5th with the TKO whereas 5th gear in the Magnum is perfect.

    5. #5
      Join Date
      Sep 2014
      Location
      Sun City West, AZ
      Posts
      672
      Country Flag: United States
      It would depend on the main intent. Do you want to be competitive autocrossing or maximize your fuel mileage on the freeway. The T56 offers a 1.78 or 2.10 second gear ratio and the TKO600 offers a 1.89 or 1.98 second gear ratio. The T56 offers a 5th & 6th gear ratio set of .80/.63 or .74/.50. The TKO 600 offers a 5th gear ratio set of .68 with the 1.98 second gear model or .82 with the 1.89 second gear version tranny.

      If you want to be competitive with no regrets you want to pick the tranny with the second gear that suit you best without running out of second gear on most courses. I am using the TKO600 with the second gear ratio of 1.89 with a rear diff ratio 3.54 behind a 646 hp motor that will spend up to 7800 rpms. Although, I have my review limiter set at 7K, I will see pick speed in second gear at 78 mph with 335-30-18 rear tires on my 89 C4 Corvette. I don't care about freeway fuel mileage.
      --
      Kenny Mitchell
      [email protected]

    6. #6
      Join Date
      Aug 2015
      Posts
      43
      Country Flag: United States
      Thanks all for the replies.

    7. #7
      Join Date
      Aug 2015
      Posts
      43
      Country Flag: United States
      Thanks. I’m not as worried about the freeway stuff. I live in a rural area and most of my driving on open roads will be 60-70. So .64 OD is fine. My main concern was the reliable shifting. If I am able to do the engine upgrades I would like in the next few years, max I would plan to shift at is 7k.

      And no I don’t plan on making the car a dedicated auto-x setup. Thanks for ur insight I like that feedback.

      My car will be more of a fun street with the possibility of doing and auto X or a track day event. I’m just 1.5hrs from Bowling Green Ky. So would not mind doing one of their track day events.

    8. #8
      Join Date
      Apr 2001
      Location
      The City of Fountains
      Posts
      15,971
      Country Flag: United States
      Quote Originally Posted by jgreene70 View Post
      .... My main concern was the reliable shifting. I’d i get the engine upgrades I would like in the next few years max I would do is 7k on shifting

      ....
      T56 Magnum...

      Andrew
      1970 GTO Version 3.0
      1967 Cougar build
      GM High-Tech Performance feature
      My YouTube Channel Please Subscribe!
      Instagram @projectgattago
      Dr. EFI
      I deliver what EFI promises.
      Remote Holley EFI tuning.
      Please get in touch if I can be of service.

      "You were the gun, your voice was the trigger, your bravery was the barrel, your eyes were the bullets." ~ Her

    9. #9
      Join Date
      Sep 2010
      Location
      Orange County, CA
      Posts
      665
      I have a TKO behind my 600 hp big block Chevelle. It works great. I went with a T56 on my current 55 Chevy build, but it’s not on the road yet. As you already know the T56 is a larger trans so it’ll take more work to make it fit. If you can do sheet metal work yourself I’d probably go with the T56. If you can’t do sheet metal then maybe the TKO is a better choice for you.

    10. #10
      Join Date
      Dec 2010
      Location
      Fredericksburg, VA.
      Posts
      3,155
      Country Flag: United States
      Here is a link to the Tremec gear ratio calulator which will allow you to play with both transmissions to see which you prefer.

      http://tremec.com/calculadora.php
      Steve Hayes
      "Dust Off"
      68 Camaro

      Given sufficient initial acceleration, even pigs can fly!

    11. #11
      Join Date
      Aug 2015
      Posts
      43
      Country Flag: United States
      I actually downloaded their app played with the numbers. My 285/35-18 with 3.89 gears and a 1.78 second gives me 72 mph@6500 and a 1.89 68 mph@6500

    12. #12
      Join Date
      Sep 2014
      Location
      Sun City West, AZ
      Posts
      672
      Country Flag: United States
      My TKO600 has the Sidewinder II shifter and I have no problem shifting above 7,000 RPMs to any gear especially through the gate. However, you do have to allow the shifting mechanism do it's job from 2nd to 3rd by just palming it up and not by moving the shifter like an OEM shifter.
      --
      Kenny Mitchell
      [email protected]

    13. #13
      Join Date
      Aug 2015
      Posts
      43
      Country Flag: United States
      Who spec’d your TKO?

    14. #14
      Join Date
      May 2013
      Posts
      42
      Country Flag: United States
      Quote Originally Posted by Schwartz Performance View Post
      <<<<<<< On the T56 bandwagon. Stick a better shifter in it from one of the trans companies (AP, SST, Bowler, Hurst) and never look back.

      -Dale
      If shifter location is not a concern what is the upside to the different shifters? Any one in particular you recommend?

    15. #15
      Join Date
      Aug 2015
      Posts
      43
      Country Flag: United States
      T56 ordered

    16. #16
      Join Date
      Jul 2012
      Location
      San Francisco, CA
      Posts
      45
      Country Flag: United States
      While an expensive undertaking you have entered the world of modern smooth shifting that will actually shift at high RPMs and take the abuse. I have a 1000-1200rwhp turbo LS9 backed by a McLeod RXT HD1200 twin disc and 100% stock T56 Magnum handling all I can throw at it.... plus 7800rpm shifts.

      You made the right choice!
      69 Chevelle 1000hp turbo LS, T56 Mag, JRi coilovers, Watts/torque arm 9", 14" Wilwoods, Recaro CTSv seats, cromo cage, a/c, p/s, built by Coffey Fab Nashville, TN.
      93 RX-7 1200hp turbo LS9, T56 Mag, 8.8", 9.3@163mph + 197mph 1/2 mile

    17. #17
      Join Date
      Oct 2018
      Location
      San Jose, CA
      Posts
      523
      Did you go with the 2.66/2.10 version or the 2.97/2.10 version?

      I've been playing with the calculators and speeds with various rear gear possibilities for a similar motor combo in a similar use car.
      The combos that I seem to like best overall are 3.5 with the wide ratio and 3.73 or 3.90 with the close ratio. Main difference in these two setups is the RPM drop on the 3-4 shift. Almost every other situation is pretty much identical. With my tire size (26") that shift happens at 90. Which is a speed at which it doesn't matter too much except on the road course - which is a corner case use case for me anyway.
      Wide ratio drops from 6K to 4100 and close ratio drops from 6K to 4600. Well - my motor makes peak tq at 4500 (500) and makes very fat tq from 3-6K and power to 6500. Probably similar to your stroker motor just with about 50 more HP/TQ in my case.

      Otherwise the drops on the 1-2 shift and 2-3 shift happen at basically the same speed and same drop between these two combos.
      48 and 68mph at 6400rpm or so.

      Cruise RPM is also basically the same too.

      Really the only difference between the two is the 3-4 gear drop is bigger in the wide ratio. But that's such a corner use case.

      I'm thinking wide ratio with a 3.5 gear is the best all around set-up and gives me a 2100rpm 75mph cruise gear.

      curious how you made this decision.
      1971 Camaro - 406 / T56
      2016 Camaro SS convertible
      2018 Colorado 4x4

    18. #18
      Join Date
      Apr 2001
      Location
      The City of Fountains
      Posts
      15,971
      Country Flag: United States
      The other difference is that with a 3.5ish rear gear, the driveshaft speed will be lower at any given mph.

      Andrew
      1970 GTO Version 3.0
      1967 Cougar build
      GM High-Tech Performance feature
      My YouTube Channel Please Subscribe!
      Instagram @projectgattago
      Dr. EFI
      I deliver what EFI promises.
      Remote Holley EFI tuning.
      Please get in touch if I can be of service.

      "You were the gun, your voice was the trigger, your bravery was the barrel, your eyes were the bullets." ~ Her

    19. #19
      Join Date
      Oct 2018
      Location
      San Jose, CA
      Posts
      523
      Shaft is going less rpm than engine in gears 1-3 and same as engine speed in 4th and faster than engine in 5th and 6th.

      So if 5th and 6th are only used for low rpm cruising that’s really a don’t care in my mind.

      You better have a driveshaft capable of 7000 rpm. With a .8 overdrive that gives you a max engine speed in 5th of 5600.
      That’s way over 100mph for any gear I would use. I’m never going over 100 in 5th.

      So that’s a moot point. For me.

      With 3.90 my car would have a top speed of 130 at engine and driveshaft speed of 6500. That’s plenty for my needs.

      If you were going to be running standing mile or open road race events that would matter. I won’t. I have done the silver state in a 1991 corvette with 4.30 gears. Ran up to 165mph in 5th. That was some crazy driveshaft speed but had a nicely balanced aluminum driveshaft.



      Anyway yes good point this is a consideration you should understand. For me it’s a don’t care however.
      1971 Camaro - 406 / T56
      2016 Camaro SS convertible
      2018 Colorado 4x4






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