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NP 205 Question Whats needed to swap

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by 74Jimmy, Jan 29, 2003.

  1. 74Jimmy

    74Jimmy Registered Member

    Mar 2, 2002
    Likes Received:
    Corpus Christi, Tx
    I have a 74 Jimmy with a 350/350/203 and D44/12bolt from a 78 blazer. Someone at sometime did a bad part time conversion on the t-case, to make a long story short I have diconnected the front drive shaft to be able to drive the truck. I have in my possesion a sm456/205. I want to use the 205 in place of the 203 what am I going to need to do this swap? Thank you in advance for the info.

    Randy /forums/images/graemlins/thumb.gif
  2. u2slow

    u2slow 1/2 ton status

    May 9, 2001
    Likes Received:
    BC Canada
    You need an np205 and adapter that originally came off a TH350. It will bolt right onto your tranny. Its the only 205 that hase the right spline count - 27.

    Here's the adapter:

    BTW: get the shifter too.. the 203 shifter won't work.

    You could also call up ORD and order their Doubler /forums/images/graemlins/laugh.gif
    It uses the front half of your 203, and mates it to a 32-spline NP205. Maybe worth considering if you can only find TH400-type 205's in your area.
  3. Leadfoot

    Leadfoot 1/2 ton status Premium Member

    Nov 28, 2000
    Likes Received:
    Western Massachusetts
    You need the above mentioned cast iron adapter, the steel female/female drivesleeve, the shifter, and a 27 spline male input gear for your 205 (the 465 version of the 205 has a 10 spline male or 32 spline female input).

    Average cost of the cast iron adapter new $200+
    Average cost of the drivesleeve new $75
    Average cost of shifter and components $30+???
    Average cost of new 27 spline input shaft $200+

    It might be cheaper to get a 205 originally from a 350 or consider a different swap.

    Also if you go the route of a TH400, you will need the above items (for a 400 instead of a 350), plus added cost of machining the case for the larger input bearing.
  4. j20m715

    j20m715 1/2 ton status

    Aug 25, 2001
    Likes Received:
    Hey Randy
    I have a 27 spline input gear, let me know if your interested.

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