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Technical Thoughts on '57 Chevy Tranny Options?

Discussion in 'Traditional Hot Rods' started by Wildman1, Aug 26, 2018.

  1. Wildman1
    Joined: Jul 10, 2009
    Posts: 193

    Wildman1
    Member

    Hey Everyone

    I have always run a 4 speed ****** in my '57 "G***er" - Mild 454 BBC (460 ci), mostly street driven

    Due to getting older (& lazier) I have pulled the 4 speed set-up & want to install an automatic. Being unfamiliar with either, and having good cores of each, should I go with a Turbo 400 with shift kit or a Turbo 350 with shift kit?

    Thanks in advance
     
  2. shadetreerodder
    Joined: Aug 4, 2006
    Posts: 291

    shadetreerodder
    Member

    swade41 likes this.
  3. 1934coupe
    Joined: Feb 22, 2007
    Posts: 5,262

    1934coupe
    Member

    They are both good choices but with that many inches I would go for the 400. I am in the same situation as you only with a SBC 377". You might also want to consider a glide. But in mostly stock (shift kit) the 400 is probably the strongest but it uses the most amount of HP to turn although I never noticed this for my purposes (stock and super stock consider this factor). Where are you located? I got a couple of worked PG's here you could try.

    Pat
     
    j-jock likes this.
  4. slowmotion
    Joined: Nov 21, 2011
    Posts: 3,697

    slowmotion
    Member

    Turbo 400 is what the General put behind the big blocks when the auto-trans box was checked. I had one in my youth, and abused it like any testosterone fueled young buck was expected too. Helluva transmission in my book. Made numerous 4-spd hot-shots tuck tail & grumble, all the way home...:eek::D
     
    texasred likes this.
  5. oldsman41
    Joined: Jun 25, 2010
    Posts: 1,556

    oldsman41
    Member

    400 for sure beefier. But if your driving on the street and got a low gear rear like 3:54. 3:73 or up why not a 700r4 beefy and od. Just a thought and option.
     
  6. 700R4 would need to be beefed up behind that engine. Which can be done, it's just somewhat more involved.
     
  7. Jmountainjr
    Joined: Dec 29, 2006
    Posts: 1,904

    Jmountainjr
    ALLIANCE MEMBER

    Based on your description of use - mild BBC mostly street driven - the 400 would be my choice.
     
  8. kursplat
    Joined: Apr 22, 2013
    Posts: 295

    kursplat
    Member

    i'll be odd man out - 2004r. http://extremeautomatics.com/th2004R.php << not necessarily recommending this place, although i've heard many good things, but they have a lot of info i needed deciding between this and a gear vendor for a non HAMB project.
     
  9. swade41
    Joined: Apr 6, 2004
    Posts: 14,520

    swade41
    Member
    from Buffalo,NY

    Out of your 2 choices the 400, although I have a friend with a 427 (435hp spec) using a th350 in his 56. I kept my built th350 in my Henry J when I switched to big block, haven't driven it yet but it's already in the back of my mind as the weak point.
     
  10. Wildman1
    Joined: Jul 10, 2009
    Posts: 193

    Wildman1
    Member

    Thanks guys!

    I was already leaning in the Turbo 400 direction, and you all reinforced my train of thought.

    Turbo 400 for the win! - NOW, what is a good torque convertor for street/performance use?

    (Remember, I'm a life-long Muncie user - this auto ****** stuff is new to me!)
     
    swade41 likes this.
  11. 56sedandelivery
    Joined: Nov 21, 2006
    Posts: 6,694

    56sedandelivery
    Member Emeritus

    Stick with the TH400, but convert it to a switch pitch ST400; uses a torque converter that can be "switched" between two different stall speeds; a street stall and a little higher race stall, if you will. "squirrel", here on the HAMB, can provide you with the details; finding the parts/transmission to use the parts from, may be the hard part. Olds/Cadillac/and possibly Pontiac used this transmission. They say to use the smaller torque converter from the ST-300. What I've wondered, is if the pump from the ST-300 can be used in a TH400 to do the conversion? Since the stator and input shaft splines are the same.....................................anyone know? I am Butch/56sdedandelivery.
     
  12. swade41
    Joined: Apr 6, 2004
    Posts: 14,520

    swade41
    Member
    from Buffalo,NY

    Lot of things come into play with converter selection, engine specs, weight of car, rear gears and intended usage. Sometimes it's best to have that info when calling a reputable converter maker.
     
  13. 57JoeFoMoPar
    Joined: Sep 14, 2004
    Posts: 6,509

    57JoeFoMoPar
    Member

    Given any consideration to the 4L80E? It's essentially a TH400 with OD, they share like 80% of the parts. They're plentiful as they were the transmissions used in GM 2wd trucks for years, and now the prices of the control units have come way down. The TCI EZTCU is like $700 and all you need is a TPS sensor, which is like $100. Is it more money than just running a regular old TH400? Yes. For sure. But depending on what rear end gear you're running, and considering you say you drive mostly on the street, you may really appreciate the OD for the civility and drivability of the car. Something to consider.
     
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  14. I remember pulling the T-10 out of my '32 and putting a 400 in it. Wouldn't do it today.
     
    OLSKOOL57 likes this.
  15. lumpy 63
    Joined: Aug 2, 2010
    Posts: 3,377

    lumpy 63
    Member

    I remember laying on my back in my parents garage and pulling a turbo 375 onto my chest and bench pressing that SOB into place in my 56 Bel Air. Made my own bellhousing side mount brackets and used a 1st gen camaro crossmember. No wonder I hurt so much nowadayso_O In case anybody's saying what the hell is a turbo 375? Its that funky 1965 or so turbo 400 with a turbo 350 size output shaft...
     
  16. Hnstray
    Joined: Aug 23, 2009
    Posts: 12,357

    Hnstray
    Member
    from Quincy, IL

    Actually, there are two TH 375 models...an A and a B. One is a beefed up TH 350 and the other a ‘detuned’ TH 400......
     
  17. kursplat
    Joined: Apr 22, 2013
    Posts: 295

    kursplat
    Member

    just couldn't make up their minds, huh?
     
  18. 327Eric
    Joined: May 9, 2008
    Posts: 2,203

    327Eric
    Member

    I would use a Turbo 350. slightly lower gear ratios, lighter weight and less power to run. And they are strong enough to handle a big block, and towing duties.
     
  19. sdluck
    Joined: Sep 19, 2006
    Posts: 3,332

    sdluck
    Member

    4L80 overdrive turbo 400 gets my vote
     
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  20. Jimmy2car
    Joined: Nov 26, 2003
    Posts: 1,707

    Jimmy2car
    Member
    from No. Cal

    I'm also a big fan of any transmission with an Overdrive.
    They just give you the best of both worlds in that you can gear
    the car for great acceleration & still have great cruising gear/low rpm
     
  21. bobss396
    Joined: Aug 27, 2008
    Posts: 18,752

    bobss396
    Member

    I always liked the TH400 myself, it all depends on what you want to do with it. I have a couple salted away for future projects, they at least make for a good core. How much cheaper is a TH350? Probably not much. I was looking for a performance automatic last year... had a wet dream project running through my brain pan.

    This local shop builds a lot of good stuff for whatever you want to do.
    http://www.fbperformance.com/GM-Transmissions/
     
  22. Wildman1
    Joined: Jul 10, 2009
    Posts: 193

    Wildman1
    Member

    Thanks Guys for the great options!

    Since I have a good TH400 core I'm going to go that route. I'm leaning towards a "Freak Show Converters" convertor - any bad experience? Thanks!
     
  23. Hnstray
    Joined: Aug 23, 2009
    Posts: 12,357

    Hnstray
    Member
    from Quincy, IL

    Have your rebuilder install the 2.75 1st gear planetary set (vs usual 2.48 set)....stock GM piece used on various models

    Ray
     
  24. Wildman1
    Joined: Jul 10, 2009
    Posts: 193

    Wildman1
    Member

    Showing my ignorance, but what is the benefit?

    Thanks for your reply!
     
  25. Jmountainjr
    Joined: Dec 29, 2006
    Posts: 1,904

    Jmountainjr
    ALLIANCE MEMBER

    With the 2.75 first gear it will pull harder off the line. Second gear is 1.48, so it will some what get you closer to an equal ratio jump first to second and second to direct.
     
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  26. Elcohaulic
    Joined: Dec 27, 2017
    Posts: 2,213

    Elcohaulic

    I did the 2.75 first gear set once, never really noticed much from it and it was expensive!!

    Nothing like a Turbo 400 with a Hurst Autostick I shifter...
     

    Attached Files:

  27. I also vote for the TH400 for service behind the big block. I converted from a 4 spd to a 400 with a Transgo shift kit in 1973, and am still using the same transmission. I am also running synthetic ATF, and that helps reduce heat and increase shifting speed.
    Regarding the converter, I have gone back to a stock converter to match my more moderated driving habits. I like switch pitch torque converters, but you would want to talk to guys like Squirrel or one of the other people regarding the modifications required to make this change. To do this, you have to have the appropriate 400 case that was designed to accept the switch pitch modification, and you will need to pull the ****** apart to make the required internal changes.
    Bob
     
  28. Wildman1
    Joined: Jul 10, 2009
    Posts: 193

    Wildman1
    Member

    Thanks for the great info!
     
  29. swade41
    Joined: Apr 6, 2004
    Posts: 14,520

    swade41
    Member
    from Buffalo,NY

    Also make sure your th400 is not the bolt in yoke variety, that's a whole nother can of worms to avoid if you can. I made that mistake once and sure wish I knew about the problems, I would have had the output shaft changed to regular slip yoke variety in a heart beat.
     
    lumpy 63 likes this.

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