Help to choose Torque Converter

Engine, Transmission & Driveline

  1. Zwap

    Zwap Member

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    The car and engine:
    -66 Polara, 383 0.030 (389 cu.i.) flat forged pistons @0.019 down the hole, Edelbrock RPM intake, E-Body HP manifold, 2.5 double exhaust, 650 AVS2 carb, cold air intake air cleaner, 3.23 Auburn rear end, 915 heads, stock rebuild -66 727 with a valve body from -71 (with part throttle kickdown), full throttle shift @ about 4.700 rpm..
    As the C-Body is a heavy car I choose the very mild Lunati 256/262 cam (Voodoo Hydraulic Flat Tappet - Chrysler 361-440 256/262) and I'm very pleased with the performance the last 3 years.
    I've got the power where I want it.

    BUT I have the stock TC and it have a stall speed @ about 1500rpm (measure from when the tires start spinning during breaking) and even if the cam makes a good torque down low, the stall speed is to low to get a decent start from standing still. (The RPM intake kills a bit of low end but I have the "regular" Performance intake before and will never go back, the RPM intake is my absolute favorite).
    I want at least another 500rpm stall speed but not too high, I still want to use the car as a daily driver.
    I'm from Sweden and it's difficult to get a custom buid so I'm looking for one of the shelf and these two are avalible at my local shop:
    Hughes Performance Street Rod Torque Converters 24-20
    Or would I not feel any difference from stock TC?
    Or should I go with this? Hughes Performance Street Master Torque Converters 24-25
     
    Last edited: Jul 2, 2020
  2. Davea Lux

    Davea Lux Old Man with a Hat FCBO Gold Member

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    For starters, you for sure do not want a Hughes 24-25. That convertor is for externally balanced applications only. You have an internally balanced engine. You will get some performance gain from the Hughes 24-20 out of the hole. That is going to be at the cost of fuel economy, That extra 500 rpms of stall at the low end will probably cost you about 2-3 mpg. You have a very mild cam, so I am not sure a higher stall convertor will be cost effective for the minimal performance gain. The are a couple of other alternatives, you could grab a '68-'70 road runner or charger RT convertor that was rated at about 1750 for a stall speed and it would cost you less money. Another alternative would be lower profile tires on the vehicle, that would have a similar effect as a higher stall speed. Gear ratios also effect stall speed. If you do mostly urban driving you could also consider a 3.55 gear set. Lots of ways to skin a cat.

    Dave
     
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  3. Zwap

    Zwap Member

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    Well Hughes wrote: The 24-25 is a neutral balance converter. If you want a bolt and go externally balaced converter, you need the 24-25 440 BAL
    The "performance" I'm after is to get higher rpm to get of from standing still when flooring.
     
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  4. cbarge

    cbarge World Famous Barge in a Budget FCBO Gold Member

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    Spend the extra money by talking to Frank Lupo of Dynamic Convertors.
    He does Mopar only and can custom build you a convertor to match your needs.
    Dynamic Converters / Pro-Formance Transmissions
    Based on thier website,500 RPM over stock would be thier 12" street convertor--but talk to them first give them all the specs you have.
    Hope this helps
     
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  5. 70bigblockdodge

    70bigblockdodge Old Man with a Hat

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    If you had the availability of a good rebuilder I would say just get yours "loosened" a bit. You might be able to find someone who can do it over there. I don't think a Volvo torque converter works on radically different principals as your Polara.
     
  6. 66 Monaco 500 365

    66 Monaco 500 365 New Member

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    Something to think about, if you haven't changed out the stator support, the '66 trans uses the old style torque converter like the cable shift 727s.
    From 1967 up, they use a different stator support with a different spline count. The change to the front pump is simple and not very expensive. I've done this mod to all my '66 727s so the selection of converters is much larger.
    My $.02
     
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  7. Davea Lux

    Davea Lux Old Man with a Hat FCBO Gold Member

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    I must be working from an old spec sheet. That convertor used to be spec'd for 440-6 or '70 and later TNT,HP or Magnum. For that they had external weights welded on. It appears that it is also offered in a neutral configuration as well, so that would work. Probably overkill for your mild cam though.

    Dave
     
  8. 66 Monaco 500 365

    66 Monaco 500 365 New Member

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    I used a stock 340/Roadrunner 10 2/3" on my A12 clone, my 440 stalled that converter at ~2500.
    Make sure you are running more cooling on your trans with any higher stall converter.
    Another $.02
     
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  9. Zwap

    Zwap Member

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    Yepp, forgot to mention that the 19 to 24 splines conversation will be made when changing converter.