8" Torque Converter - Strip AND Street??

Transmission and Drivetrain Tech

  1. Demonx2

    Demonx2 FABO Gold Member FABO Gold Member

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    Looking for some input from those of you who may have "been there, done that" (or are currently doing it). My build is a 72 Demon with a new 408 stroker/727 trans. Engine dyno'd at about 525 #-ft and roughly the same hp. This car will be a 95% strip/5% street car. It's got a 4.56 axle (may drop it to 4.10) and will weigh about 3200-3300 with me in it. Can't say for sure on everything as other than the engine, the car is still in the build phase.
    I've talked to many of the torque converter companies about an appropriate converter for this combo. Likely looking at something in the 4500-5000 flash stall (it's a foot-brake car) so there are various ways to do that. Either a "tight" (or more efficient) 8" or a "loose" (ie. inefficient) 10" (or 9.5") converter. I'm leaning towards the 8" due to this car's intended purpose as a fun and quick track car first. But my question is if anyone has used an 8" and actually driven it on the street and made it work. The car has a BeCool alum radiator with a trans cooler in it and a separate trans cooler as well. But if the car was used to drive to a local cruise or car show or something that is 10-20 miles away, has anyone been able to get away with an 8" converter without overheating the trans? Also, how about just normal driveaways from a stoplight - how high in rpm does it go before it moves the car?
    I have a 10" TCI converter that flash stalls at around 3300 in another car (440 engine/4.10 axle) and you wouldn't know it had a non-stock converter in it under normal driving. And it never even hints at getting the trans too warm.
    So as always, looking for any experience and collective wisdom that's out there using an 8" converter or other similar stall range converter. Thx for your input!!
     
  2. Demonracer

    Demonracer 71 Demon 00 Ram 16 Chrysler 300S 05 Caravan FABO Gold Member

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    Which ever converter you choose, be sure you add a transmission cooler if you drive it on the street. Stall converters build a lot of heat with street driving & will cook the fluid fast.
     
  3. Oldmanmopar

    Oldmanmopar Going left turning right FABO Gold Member

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    I used a 8 inch 5500 tight with 456's ., I drove it on the street with full exhaust. I liked it. I also have a 3500 and a 4500. I really liked the 8 inch 5500 tight. It flashed around 5000. The cam was a 686 solid roller. Here are some videos of the car on the street and at the track.

    Boy I miss this car, I think it kept me young. The day my son totalled it I actually cried. I drove it on the street for over 6 years with that converter.



     
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    • toolmanmike

      toolmanmike FABO MODERATOR Staff Member FABO Gold Member

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      Wow! Looks like fun. That thing was nasty! (in a good way)
       
    • RustyRatRod

      RustyRatRod Bla de blizhibliz de blatde blizi bla bla FABO Gold Member

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      Converter diameter has little to do with modern converter stall speed. Not like it did years ago. Like @Oldmanmopar said, you can get a 5000 stall and drive it on the street......and it will lock up plenty enough to pull good and get decent mileage without generating a lot of extra heat. When you drop the hammer though, it'll flash to 5K. That's a modern converter. They do things unthinkable even ten years ago. But no matter how much you preach it, few people listen and they always chicken out and go for somethin stupid. The converter is the single most important consideration with an auto equipped vehicle. It can make or break an otherwise good car.
       
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      • RustyRatRod

        RustyRatRod Bla de blizhibliz de blatde blizi bla bla FABO Gold Member

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        I've always loved that last video. You could tell those guys had never seen a street car do that kinda thing.
         
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        • 66 Dart 273 hipo

          66 Dart 273 hipo Active Member

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          I’ve got a 8 inch in my 340 right now. Love it. Drive it on the street 90 percent of the time. If you have a good cooler on it and don’t do dumb things like sit at a traffic light in gear you’ll be just fine. I use a trans temp gauge in the line coming out of the trans (hot spot) to monitor it. You’ll never. go back. Also a model J Will work good but I’d still go with the 8 inch.
           
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          • toolmanmike

            toolmanmike FABO MODERATOR Staff Member FABO Gold Member

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            Last video: "Get that?'' "Hell ya!" :rofl: Never straight, always forward!
             
          • hemi446

            hemi446 Well-Known Member

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            I helped a friend with his 68 Dart he runs a 8" ATI 4200 with 5.13 on the street from time to time can drive it all he wants and it doesn't seem to be a problem. My son has a 426 small block with a 727 8" ATI 4500 converter and 4.30 gears and it works fine on the street.
             
          • Demonx2

            Demonx2 FABO Gold Member FABO Gold Member

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            That was/is(?) a beautiful car!
             
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            • Demonx2

              Demonx2 FABO Gold Member FABO Gold Member

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              This is the input I was looking for - sounds like others have done what I am contemplating: an 8" on the street. I understand you can't take it on a 50 mile drive but it seems like with a decent cooler/fan set-up, it should be ok on a 5-10 mile ride to a cruise spot. Any comments on what rpm looks like on a light-throttle driveaway from a red light? I just want to make sure it's not screaming at 3500 rpm just to pull away in normal street driving.
               
            • oldkimmer

              oldkimmer FABO Gold Member FABO Gold Member

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              U will never know it’s in there till I stand on it. Kim
               
            • B3422w5

              B3422w5 Well-Known Member

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              Had several cars, ranging from 9’s to 11’s in the 1/4.
              Drive/ have driven them all on the street extensively.
              All with 8 inch convertors.
              Tight, loose, get what makes the car ET the best.
              And enjoy it at the track and on the street
               
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              • famous bob

                famous bob mopar misfit

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                best 727 torqueflite convertor companies are ?????????
                heard dynamic has been sold .
                May break down and order one ,have a hughs 3500 in the fish now , no real complaints with it tho-----------
                 
              • B3422w5

                B3422w5 Well-Known Member

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                i have always ran PTC convertors with one exception( ATI)... have 5100 PTC in my street strip Dart
                 
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                • oldkimmer

                  oldkimmer FABO Gold Member FABO Gold Member

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                  Once u have a great converter u will never go back. It’s the single most important part of ur build. It makes a good car a great car. Kim
                   
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                  • '63GT

                    '63GT FABO Gold Member FABO Gold Member

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                    I tried to hit 'agree' 3-4 times, but it only counted 1, so..
                    AGREE !!!
                     
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                    • Demonx2

                      Demonx2 FABO Gold Member FABO Gold Member

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                      My research and you comments have convinced me - an 8" it is with a stall around 4800-5000. Likely will be an ATI. Thx again for the input.
                       
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