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203 on a 208 x-member ?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by R72K5, Nov 1, 2003.

  1. R72K5

    R72K5 Banned

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    lets say if you had an 83 k-10 with 208 and 700r4 and you then put in a 77-79 203 case with th350, would the 203 case sit farther down or anything than the 208 did?

    thanks
     
  2. R72K5

    R72K5 Banned

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    ok..

    does anyoen know if 208 x member in 83 84 was drop down or not ?

    the 79 k20 203 x member under neighbors truck is drop down and case and tranny sit nice and level under truck

    it appears that the 203 case under the 83 84 k10 with 208 x member is sitting way down too far

    this is what im trying to find out about

    i know that in 80 or 81-up there were two different 208 x members, one w-shaped and one not, i dont know which is lower than the other, or if a 203 would even bolt to either using the common iron th350 stand up adapter ?

    thanks
     
  3. stretch67

    stretch67 1/2 ton status

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    i have a 1984 crossmember from a 700r4-np208 and a 1974 from a th350-np203 i am running a th400-np208 setup in 1967 gmc first i had the 74 crossmember in place and it looked like the front driveline would hit at the cv joint the 84xmember looked like it dropped lower so i pulled the 74 one but when i had both on the floor side by side the height was the same! the 84 has a concave spot where the cv joint is on the t-case so i used that one the cross members look different but are same drop but the 208 case does stick down quite a bit further than the 203 did hope this helps! /forums/images/graemlins/confused.gif
     
  4. R72K5

    R72K5 Banned

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    im pretty losted now i think, well one thing that affects this is that im pretty sure th400 main case is not same length as th350 and 700r4

    so hmm.
    but.. thickness of adapter for th400 is probably not same thickness as for th350 and/or 700r4

    i asume that there were only two heights of adapters, one for straight drop x member and other adapter height for w-shaped 80s 208 x member

    right ? or ?

    thanks!
     
  5. SCOOBYDANNN

    SCOOBYDANNN 1/2 ton status

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    dont know if this will help, but I had a 465/208. I swapped in a 400/203 and used the 465/208 x-member and everything bolted right in--crossmember holes, adaptor bolts and driveshafts.
     
  6. 4GUNZ4X4Z

    4GUNZ4X4Z 1/2 ton status

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    I swapped from a 700/208 to a 350/203 and used the same crossmember from my 208 on an 84K5. I had to drill new holes in the frame, but it was no big deal. I have 1" spacers between the crossmember and frame. Its been 2yrs now and havent had any side effects.
     
  7. R72K5

    R72K5 Banned

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    hmm interesting, i dont think this kid had to drill any hoels when he put the 350 and 203 under the truck, hmm,..

    thanks
     
  8. 4GUNZ4X4Z

    4GUNZ4X4Z 1/2 ton status

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    /forums/images/graemlins/thinking.gif I had to move mine about 1.5".
     
  9. 84_Chevy_K10

    84_Chevy_K10 Banned

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    84 crossmember is the flat one. They didn't change it til 85 or so. My truck has the stock crossmember and a 79 465/205 combo.
     
  10. R72K5

    R72K5 Banned

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    so maybe 83 k20 208 465 member is hte oddball one being W shaped ?
     

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