TH350 vs TH400: I have a couple questions and need help

Discussion in 'Transmission & Driveline Topics' started by LDBrock87, Dec 2, 2017.

  1. junkyardZ28find

    junkyardZ28find Veteran Member

    731
    7
    Mar 4, 2012
    des moines, iowa
    Holy sheeoot. I helped a buddy about 9 years ago with a 434 smallblock and we had a Little M block, a pair of Brodix Track II heads, a Super Vic intake, .544/.565 solid roller cam, blah blah and the owner even topped that off with a Titan Nitrous plate system at the time...he had paperwork showing 675 HP (just on motor) at iirc 5800 RPM. I cant even imagine less cubes and nearly 200 more HP...! First pass off the trailer I remember that motor pulled an all steel, full interior '66 Chevelle down the 1/8th at 7.52 @ 88 mph before we dialed in a few things to get a best pass in the 6.90s. That was with a Moser 12-bolt and 4.10s. We never even tried the nitrous yet....had it jetted for a 200-shot and maxed out that thing would allow for a 750 shot!

    Lets see some pics of this badd mofo!!
     
    Blown Camaro likes this.
  2. 1980RS

    1980RS Veteran Member

    1,595
    12
    Jun 17, 2006
    Well I would not even think about a turbo 350 with that much power, 400 all the way. I hope you don't think you anyone is going to make you an 800hp 383 with a production block. You will need some real big heads and a giant cam to make that kind of power N/A and it's not going to be very streetable. If a builder is telling you he can get 800 out of that make sure you have him put the engine on a dyno, before you pay him any money. I would be very leery on his hp estimate.
     
    Blown Camaro likes this.
  3. Lowend

    Lowend Administrator. .a car, a man, a maraca. Staff Member Lifetime Gold Member

    14,144
    173
    Mar 25, 1999
    San Jose, CA, USA
    Understand - I'm not trying to discourage you. It's very easy for people to spit out big numbers for engine power. Anytime I hear a number about 500HP for a smallblock, I'm skeptical. It sounds like this is probably the real thing. Although again, this probably isn't going to hold-up as a street motor at those power levels
     
  4. LDBrock87

    LDBrock87 New Member

    9
    0
    Dec 2, 2017
    I was just as critical of the estimate when I first heard it, and it is a rough estimate, that 800 is in no way exact or anything. I don’t think it’s a production block, but I can’t be sure since I haven’t had a chance to even really touch it yet with finals coming up, but I’ll defin get back to everyone on this thread when I find out. Thank you!
     
  5. LDBrock87

    LDBrock87 New Member

    9
    0
    Dec 2, 2017
    Oh you’re fine, I completely understand. It is a really rough estimate, but I know it’s a difficult thing to believe straight away. Anyway that’s one big reason why I joined this forum, to hear everything I need to be skeptical about from people with the experience I don’t have! I’ll definitely get back to you about it when I can get the opportunity to really look it over(I’m kinda repeating a lot from the reply I just posted to RS lol). Thank you so much for your help!
     
    Last edited: Dec 7, 2017 at 3:56 PM
  6. 1980RS

    1980RS Veteran Member

    1,595
    12
    Jun 17, 2006

    Sounds like you will have a nice combo when it's done. If you want to know how tough a turbo 400 is, you should see my clutch discs in this thing after 24 years of abuse, they look like new. I was mighty surprised.
     
  7. LDBrock87

    LDBrock87 New Member

    9
    0
    Dec 2, 2017
    I believe it! Quick question: even though it’s really built for the track I definitely want to still drive it normally every now and then(definitely not often but just to cruise and show it off). Do you think it would hold up fine to that? Or would it start to hurt it after too much normal driving?
     
  8. SRGN

    SRGN Veteran Member

    258
    67
    Feb 20, 2009
    Central NJ
    Define normal driving. I've done a transbrake launch from a traffic light on my way to work...
     
  9. 1980RS

    1980RS Veteran Member

    1,595
    12
    Jun 17, 2006
    I would use my turbo 400 any day on the street except that it has to be manually shifted, I set it up that way. I can convert it back pretty easy as I use the transgo kit do this. I have beat the death out of turbo 400's all my life, some went bad and it was mostly by my hand doing some wrong things, like putting in the center support retainer wrong, not once but twice ( I am a dummy on that one) so it burned the intermediate clutches and then you would noticed a soft 2nd gear but it still worked. In my street car I had a turbo 400 with 90K on it and beat on that for 15 years before I sold it and went to a 6 speed. I will see If I can put some pics of the clutches and steels for you.
     
  10. LDBrock87

    LDBrock87 New Member

    9
    0
    Dec 2, 2017
    Thank you so much! That would be much appreciated, and I just wanted to be sure:)
     

Share This Page