t56 magnum fitment

Discussion in 'Transmission & Driveline Topics' started by rosco72z, Sep 4, 2020.

  1. badazz81z28

    badazz81z28 Veteran Member

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    I'm more concerned with first gear too. With a 2.66 first gear, your starting line ratio is horrible. You might be OK with nearly 2500 rpm cruising in 6th, but realistically the gear ratio is all wrong for the transmission ratios.

    Fun for sure, but 4.10s are too deep for that trans too...I had 3.73s with my TKO 600 and it was as deep as I would go.
     
    Last edited: Sep 17, 2020
  2. G72Zed

    G72Zed Veteran Member

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    Well, that's your opinion, Tell us, when was the last time you drove a "true" 500hp BBC with a TKO600/.64 with 4.10 12 bolt ??

    Gearing has more to do with vehicle weight and engine stroke than most think, keeping the engine in a + harmonic is key, not to mention carb/intake/port design choice.Nobody asked what cubic inch it is.

    The owner road races another car, he drives this Chevelle 15 hours to VIR while his partner drives the motor home/trailer. Then, he brings people for laps in the Chevelle...

    He goes and drives 3 hours to the track, and bangs off easy mid 12's all day without sweating it, the guy can drive, shift like a MF and for a dude pushing 60 years old, he's having a blast.
     
    Last edited: Sep 17, 2020
  3. flht99b

    flht99b Veteran Member Gold Member

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    Posted this numerous times, my 71Z has 4.10's, 28" rear tire, TKO 600 with .64 fifth, 400hp carbureted gen 1 SBC. 2200rpm at 70mph and borderline on efficiency. Although I can run along fat dumb and happy and accelerate at 2000rpm in fifth, it is not efficient at all. A change to a 27" tire will pick up approximately 100rpm at 70mph. Ideally I think a 26" tire would be pretty close to right BUT, it will make the car even more gear bound in first to fourth. As it is now with the 2.87 first gear, 4.10's and 28" tire I often start off in second gear. The TKO 600 with the .64 fifth is great at reducing rpm but the drop from fourth to fifth is nearly 1000rpm which is not ideal for performance. BTW, have a TR 6060 in my 2010 Camaro as well as the TKO 600 in my 71 Z28. Both run Red Line D4 fluid. Hands down the TR 6060 is a better shifting transmission.
     
  4. biker

    biker Veteran Member

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    Totally agree with the logic above, and there is definitely more to a successful combo than just the gearing numbers. One has to understand and be adept with fuel and ignition tuning to ensure things work well from low to high rpm. For what I do, my 383 has a pretty usable spread of power that lets me use all the gears on pump gas. The 3.73's actually make that way better. The TKO is the only new, actual performance transmission I've owned in my life, and I can tune my combo around it to work really well. I'm sure if I tried a t56, I'd see the differences in shift quality and in time, I may go that route, but it wouldn't work well with my current combo.

    Back to the OP concerns, I still say that if he can build his combo around the t56, go with that over the TKO, simply because more gears are better, and if shift quality really is that much better, then why would you not go t56 while you have the choice.
     
  5. badazz81z28

    badazz81z28 Veteran Member

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    it’s not my opinion, it’s an industry standard.

    I have a 427 in my car and have run the TKO and currently the Magnum. My car is a true 650hp....I run 12s on street tires and rolling take offs.
     
  6. 76z28

    76z28 Veteran Member

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    It really is an opinion. I can run a high 11 on street tires(nitto nt555s to be exact), but wouldn't call mine a "true 650 horse" car.
    It makes probably 600-630 and weighs about 3700lbs.

    Gearing is based on weight, my car is HEAVY and revs to about 6300--with a good tire the 4.10s would make it launch better than it currently does. It also allows me to be at 6300 at the end of the track.
    I see a LOT of late model camaros going to 4.10s(4th gen and 5/6th gen) with the t56 or tr6060.
     
  7. badazz81z28

    badazz81z28 Veteran Member

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    I think you’re missing my point...we are talking about the efficiently of the transmission, not how fast your car is. I just threw that out there because someone implied I never drove a fast car. You’re worried about launching and RPMs at the finish line. If that’s what your goal is...why a OD trans? Your basically saying you would recommend a 4.56 gear or deeper if the same question was asked about a Muncie. Nobody would do that for a street car unless they want to scream the RPMs while driving.

    As for the TR6060, do you realize 6th gear is .50 in many application? It’s not on the Magnum.
     
    Last edited: Sep 17, 2020
  8. 76z28

    76z28 Veteran Member

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    Yes, however the difference between 0.63 and 0.50 really isnt very much at cruising speed. Turning 2000rpm is not very high at 70mph. If someone was wanting to launch harder, I would absolutely tell them to use a lower gear. That is the benefit of the t56--you can have your cake and eat it too--low gears and over drive.

    The difference at 70:
    0.63 2132
    0.50 1692(unusable for 90 percent of performance cars due to cam surge)
     
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  9. G72Zed

    G72Zed Veteran Member

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    You make some very good points 76z28.

    My customer with the 69 Chevelle raced these back in the day....He wanted his mild 396 BBC to run mid 12's street trim, and on street radials, go through the traps at 5,500-5,800 rpm in 4th, and cruise in his sweet spot of 2,400 rpm at 120/123 KPH (75 mph) for our highways around hear. I built the carb and tuned/setup accordingly.

    Car comes in at 3,800 #, puts down a net 390-400 HP and goes 12.5 @110 mph on street radials, just what I figured it should do.

    He has put on 40K miles, uses the same FT hyd cam with VR1 and gets an honest 17MPG...he was actually going to drive to Las Vegas for a big convention (NAPA) but the border closed, very Happy customer.



    Please share this "industry standard", I'm curious as heck to read up on this......

    By the way, a 427 (anything) making a true 650hp only running 12's on street tires.....gee, I really hope you find out what the problem is.
     
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  10. badazz81z28

    badazz81z28 Veteran Member

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    Google SLR...Many sites have info on it.

    "By the way, a 427 (anything) making a true 650hp only running 12's on street tires.....gee, I really hope you find out what the problem is". BTW this is a pretty ignorant comment. You know ( I think you do)...there is more than just Horsepower for a fast ET. I have a full weight car, on street tires and don't launch. You also have to consider I have a 6 speed too. However lets put proof on the pavement...my car is no slouch.
     

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