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307 with a turbo 400? main differences between T350&T400?

Discussion in 'The Hokey Ass Message Board' started by murf-lostincity, Sep 27, 2008.

  1. murf-lostincity
    Joined: Aug 27, 2005
    Posts: 215

    murf-lostincity
    Member

    i am putting together a 307 with a mild cam after reading fat hack posts (thanks fat hack)

    anyways i have a friend who wants to sell me a perfect working turbo 400 outta his 69 chevy for 100 bucks is this a good match for my 307?? what are the main differneces between the turbo 350? was it the overdrive switch?

    all this is going in my 54 chevy project
     
  2. Rich Rogers
    Joined: Apr 8, 2006
    Posts: 2,018

    Rich Rogers
    Member

    The 400 is stronger . If you can grab it 100.00, get it. You won't be sorry
     
  3. lowrodderDon
    Joined: Dec 7, 2007
    Posts: 257

    lowrodderDon
    BANNED

    The turbo 400 is probly overkill for a 307, as it eats a lot of torque, but for a $100 it's a good deal.
     
  4. Lobucrod
    Joined: Mar 22, 2006
    Posts: 4,122

    Lobucrod
    Alliance Vendor
    from Texas

    Turbo 400 doesnt have an overdrive switch, it does however use a switch to control the kickdown.
     

  5. murf-lostincity
    Joined: Aug 27, 2005
    Posts: 215

    murf-lostincity
    Member

    i'll probably pick up that t400 for 100 bucks anyways

    but is it not a good idea to run it on my 307??
    with fuel economy in mind

    looking on craigslist found this for $3500 thinking about it http://mohave.craigslist.org/cto/857896909.html
     
  6. murf-lostincity
    Joined: Aug 27, 2005
    Posts: 215

    murf-lostincity
    Member

    yes the kickdown
    dont know much about t400 yet.

    eats to much torque huh that might work against me in trying to save gas
     
  7. 38plymouth
    Joined: Apr 11, 2008
    Posts: 420

    38plymouth
    Member

    As mentioned before the T400 is overkill for your 307. You'll lose 5 mpg with it. That's my experience with them.

    The main difference is the big pump.
     
    Last edited: Sep 27, 2008
  8. Pir8Darryl
    Joined: Jan 9, 2008
    Posts: 2,488

    Pir8Darryl
    Member

    T-350 eats ~27 H.P.
    T-400 eats ~38 H.P.

    On a low torque motor, like a 307, I'd go with the T-350, because the 400 will eat into MPG and make the car feel slugish off the line.

    The advantage of the 400 is that it's much stronger than the 350, and will live much longer in big cars and/or behind high power engines. However, the 350 [and 400 for that matter] is soooo simple... Anyone with a screwdriver and a pair of channel locks can rebuild one in a couple hours. Less complicated than rebuilding a carburetor, but there are more parts than a carb.

    Rebuild kit from O'rileys is ~$100, shift kit is ~$45, new converter is ~$75. So I'd go with the 350, and just plan to rebuild it every 2-3 years.
     
  9. Deuce Roadster
    Joined: Sep 8, 2002
    Posts: 9,519

    Deuce Roadster
    Member Emeritus

    I run a 400 Turbo in my 32 roadster ... and I do not find the Turbo 400 to be much more fuel consuming than the Turbo 350.
    1 to 2 mpg tops ... that's my experience :)

    [​IMG]

    It is a simple matter to come up with a electrical switch to control the kick down/passing gear feature. I also like the fact that the Turbo 400 does NOT have a cable off the side of the case that runs to the carb for than function.

    A Turbo 400 is almost indestructible ... as long as you keep fluid in it. It also is a great transmission to have if you ever plan on putting a little HORSEPOWER in your car. :D
     
  10. murf-lostincity
    Joined: Aug 27, 2005
    Posts: 215

    murf-lostincity
    Member

    It is a simple matter to come up with a electrical switch to control the kick down/passing gear feature. I also like the fact that the Turbo 400 does NOT have a cable off the side of the case that runs to the carb for than function.


    thats the same thing the guy who has the tranny said
    well i was wondering if i should or should not run it because i was concernd with fuel consumption ultimately
    i think i might keep looking for a tranny
    just seems sooo cheap what he wants for the t400
     
  11. murf-lostincity
    Joined: Aug 27, 2005
    Posts: 215

    murf-lostincity
    Member

    speaking of parts
    the guy with the tranny has a 70 something camaro front clip with complete disc brakes wondering if i should buy it?? only 100 bucks too
    i was thinking i could run the spindles and disc brake setup on my mustang11 setup??
    since disc brake kits are over 200 bucks

    what do you guys think
     
  12. murf-lostincity
    Joined: Aug 27, 2005
    Posts: 215

    murf-lostincity
    Member

  13. T400 is heavier and more durable.

    But if your 307ci is basically stock I'd just run a T350.
     
  14. Jarred Hodges
    Joined: Jul 30, 2008
    Posts: 564

    Jarred Hodges
    Member

    with a stock 307 a turbo 350 will be plenty, a 400 would be overkill and eat up to much power
     
  15. 40Standard
    Joined: Jul 30, 2005
    Posts: 5,828

    40Standard
    Member
    from Indy

    I'd use a 350 behind that 307 but would buy the 400 and flip it or save it for future use
     
  16. tomslik
    Joined: Mar 3, 2001
    Posts: 2,162

    tomslik
    Member

    IF it's a chevy case (sounds like it is), buy it, turn it, buy a 350 turbo and pocket the rest.
    chevy cased 400 trannys are getting up there in price...
    BOP's not so much...
     
  17. autobilly
    Joined: May 23, 2007
    Posts: 3,094

    autobilly
    Member

    I agree with LowrodderDon. The TH400 is heavier and takes more "to turn", but if you break TH350's (HOT 307?) then you'll be making the power to overcome this and it's worth consideration. The price certainly is good.
     
  18. fab32
    Joined: May 14, 2002
    Posts: 13,985

    fab32
    Member Emeritus

    Forget the Camaro spindles on a MII.

    Frank
     
  19. murf-lostincity
    Joined: Aug 27, 2005
    Posts: 215

    murf-lostincity
    Member

    what spindles should i use with the mustang 11 then??
    thought i should ask since i found thaqt setup for so cheap
    i kinda think it might still be worth it to take the disc brake components off???
    and use them for my project??

    thank for all the comments and advice so far guys....
     
  20. uglydog56
    Joined: Apr 8, 2008
    Posts: 331

    uglydog56
    Member

    400's don't fit as well under early floorpans either. Having said that, 100.00 is cheap.
     
  21. lowrodderDon
    Joined: Dec 7, 2007
    Posts: 257

    lowrodderDon
    BANNED

    It would be cool to put the kickdown switch on the shifter like a nitrous button and when you mash it hit the button to hit passing gear............???
     
  22. David Chandler
    Joined: Jan 27, 2007
    Posts: 1,101

    David Chandler
    Member

    Just for the record, GM put turbo 400's behind a 4.3 V6 in vans. So perhaps the power loss isn't that big of a deal? Also aren't the 400's geared lower in first and second? If so you probably wouldn't notice it so much, except for slightly less economy? I got one with a V6 that I bought.
     
  23. Shifty Shifterton
    Joined: Oct 1, 2006
    Posts: 4,964

    Shifty Shifterton
    Member

    TH400 has a slightly higher first gear than a th350 and that's to blame for alot of it's "power eating" reputation.

    Honestly I'd use either one. GM put a th400 behind the wheezing 165hp 350 in mid 70s vettes. And they also put th350s in 350 powered 3/4 ton 4x4s thru the same years. My opinion is the th350 delivers better driveability, mostly due to superior kickdown response & adjustability. But the th400 has a better name and becomes a minor selling point.

    $100 is decent price, recently the bottom's fallen out of the th400 market because OD conversions are so popular, and there's very few daily vehicles on the road using th400s anymore.

    good luck
     
  24. TH350 and TH400 both have a 2.48 gear, you are mistaken.

    TH400 is like 40-50 lbs more I think.
     
  25. Pontiac35
    Joined: Aug 27, 2005
    Posts: 52

    Pontiac35
    Member
    from Wisconsin

    If you have the mustang control arms you will want the mustang spindles, you can use the gm rotors and calipers but will need mounting hardware from the aftermarket or your garage/shop. Wheel seals#19211(I think that is a National #) Fat Mans fab lists the bearings as a #12 and #13. Only other thing I can add about the 400 is that it is a physically bigger unit than the 350. Rear gearing will have a bigger bearing on throttle response and ultimate fuel mileage. I have found out that high gearing does not equate to better mileage, got to work in the power range of the motor/distributor.
     
  26. Shifty Shifterton
    Joined: Oct 1, 2006
    Posts: 4,964

    Shifty Shifterton
    Member

    TH350 uses a 2.52 first gear, TH400 is a 2.48
     
  27. 400's are great, but 350 turbo's can be made to stand up to quite a bit of abuse with the substitution of a hardened second gear sprag. Got one behind a mild 454 in my late model ElCamino. Another thing, in addition to a pair of pliers, etc., when attempting a rebuild on a TH350; you would also need a way to compress the spring packs, the hardest one to get to is in the back of the case.
     
  28. old dirt tracker
    Joined: Sep 20, 2006
    Posts: 1,002

    old dirt tracker
    Member
    from phoenix

    you use must 11 spindles with a must 11. you can use stock ones if you can find them 74-78 must 11 of 74-80 pinto. you can buy them new repros. stock or 2" dropped.
     
  29. doozcoupe
    Joined: Mar 15, 2007
    Posts: 310

    doozcoupe
    Member

    I have a 350 bolted to my 283 (RV cam) in my 32. 3.08 rear end and I'm gettin 19 mpg on the interstate at 70 mph.
     

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