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TH350/NP205 to TH400/NP205 Conversion

Discussion in 'The Garage' started by 1972Blazer, Jun 11, 2003.

  1. 1972Blazer

    1972Blazer 1/2 ton status

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    I believe that after all the input from members and research I have done it will be best to convert to a TH400 vice the SM465. I currently have the TH350/NP205 that I will purchase the parts from ORD to convert to the larger bearing and female shaft. Do I need to have a different adapter/mount between the transmission and transfer case for the TH400 vice the TH350?
     
  2. 1972Blazer

    1972Blazer 1/2 ton status

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    I think my only other option would be to go with the female 32 spline NP205 for the SM465 vice the TH400 setup due to the strength of either of these setups. My question is do I need a different adapter/mount between the transmission and transfer case for each of these? What will this different adapter/mount cost and does anyone have one? I would prefer the TH400 adapter/mount due to the fact that I am already setup for the Automatic. But I would also prefer the SM465 due to the fact that I would maintain the position of my engine and driveshaft lengths. I guess whichever is less and easier to get. Input?
     
  3. JDNobodi

    JDNobodi 1/2 ton status Premium Member

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    I would forget about reuseing your drivelines because you are changeing the overall length of your tranny/transfercase in either setup. I believe ORD 32 spline upgrade requires a spacer for 465/205 set up.
    Now for the TH 400/NP205 set up. After you bore the case out for the bigger bearing and change the input, you can use the TH350/NP205 adapter with a 3/4" adapter to change the bolt pattern, and use the correct length output on the transmission. This EXACTLY what Advance Adapters does on their heavy duty kit for TH400 replaceing TH350(Part No. 50-3203). However, they charge $526 for this set up and it only includes a new front input, a new bearing, the 3/4" adapter, and a new shift linkage. /forums/images/graemlins/shocked.gif You probably can do cheaper if you get all the seperate parts yourself, and have a machine shop build you the 3/4 adapter. But beware, because you still need to get a rebuild kit for the 205.
    On to the tranny, My Advance Adapters catalog says you only need stock 2WD output which is a lot of help because there is all kinds of different output lengths for the TH400 /forums/images/graemlins/1zhelp.gif. My guess is the 2 1/2" stick out.
     
  4. JDNobodi

    JDNobodi 1/2 ton status Premium Member

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    To back up my claim on the 465/205 upgrade, I going to quote Stephen from this thread."We also have an adapter plate to allow you to use the factory 32 spline output shaft with the factory 10 spline adapter housing and a 32 spline NP205. This adds a little over an inch to the overall length and gets rid of the 10 spline connection all together."
     
  5. JDNobodi

    JDNobodi 1/2 ton status Premium Member

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    Arrgg! Damn it. I reading my Advance Adapters catalog and I'm getting two different thickness for thier adapter. The text says 3/4", but thier chart says .590" I have one of thier standard adapters at a friends shop. It should be the same thickness as the heavy duty kit. I go measure it tomorrow. (If I get out of bed in time.)
     
  6. 1972Blazer

    1972Blazer 1/2 ton status

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    I appreciate all your help on this!!! What about using a complete 1 Ton NP465/NP205, it should have the 32 spline shaft and no other adapters should be needed right? Is this setup the same length? /forums/images/graemlins/confused.gifThis is getting so damn difficult, what ever happened to an easy swap. I already have $850.00 in new custom 1 Ton Driveshaft setup, this will mess that up real quick!
     
  7. 1972Blazer

    1972Blazer 1/2 ton status

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    What if I move the engine forward vice the transfer case back? I have a ton of room in front of the engine, or will the front axel hit the oil pan. I am running a small block, there should be room. Then I wouldnt have to redo my drive shafts? /forums/images/graemlins/thinking.gif
     
  8. JDNobodi

    JDNobodi 1/2 ton status Premium Member

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    I believe the late model factory 1 ton 465/205 is also a inch longer than the early model 465/205, because ORD kit use a factory tranny output and tranfercase input. You should ask Stephen at ORD more about this kit. Anyway, I saw a frist gen blazer once that move the motor forward to keep the drivelines the same. I don't know the specifics how it was done. It had a 396/TH400/NP205 in it with a Advance Adapters kit. So it can be done.

    Here is more information.
    length of TH350 case = 21.50"
    length of TH400 case = 24.25"
    length of TH700R4/4L-60 case = 23.375"
    length of 4L-80E case = 26.00"
    length of 4L-60E with removeable bellhouseing = 22.00"
    length of NV4500 case = 12.375"
    length of SM465 case = 12.00"
    length of SM420 case = 11.50"
    Now these lengths only the transmission case only. Does not include the length of the adapter.
     

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