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Best way to convert my C-20 into a K-20

Discussion in '1982-Present GM Diesel' started by arveetek, Mar 4, 2003.

  1. arveetek

    arveetek 1/2 ton status

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    Okay guys, I'm going to start out asking ya'll about this first, instead of going into the 4x4 forum. I feel like I know ya'll a bit better than the others, and maybe you can point me in the right direction. I know my diesels, but I've only owned one 4x4!

    Here is the truck I want to end up with: a nice riding 3/4 ton 4X4 that doesn't sit too high. Basically, I want my C-20 just like it is except with a front diff. I don't do any off-roading, but I do get stuck in the snow and mud. I need a truck that is mostly a highway truck that can use all 4 wheels from time to time. My truck rides great the way it is; much, much better than the K-10 I had. It seems like the stock leaf springs up front on the K-10 didn't have any travel whatsoever.

    Here are the options I'm considering:

    #1 Swap in SFA with coil springs and some sort of 3 or 4 link setup. I've been reading some articles on this, and this is looking pretty tempting. I think this would be really nice. Lot of fabrication, though.

    #2 Swap in SFA with some sort of softer leaf springs...perhaps with the springs below the axle....has this been done? I haven't read anything on this option yet...seems like most guys want to go higher....I want to remain at stock height for towing my fifth-wheel, but not jar my teeth out everytime the front end hits a bump. Seems to me that some bowed leaf springs that have lots of travel mounted below the axle would be better than flat springs mounted on top of the axle.

    #3 Swap in IFS setup from '88+ model...I like this idea, I think it would great. However, from what I have looked at....I think I would have to end up cutting the entire front frame portion off the newer truck and then scabbing it onto mine...plus making the front clip fit the new frame.....not the easiest choice by far. This would probably give me the best ride, though.

    Any thoughts about this? I know, I know, it would be easier to buy a 4x4 to start with....perhaps I will. It's just that I've got my '81 all set up the way I like it. If I could find an '81-87 K-20 as nice as mine, and with an OD automatic, I'd probably go for it. Put GM didn't make 'em that way. Also, my '81 has been with me a long time, and I don't want to part with it.

    I dunno what to do.

    HELP!! /forums/images/graemlins/cool.gif

    Casey
     
  2. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    I would say K.I.S.S.

    All the holes and junk needed to do the swap are already there to go leaf over axle in the front. If you want a better ride than stock I would just get some springs built by Alcan or National to your spec's. You'll have to get some weight spec's for the front of the truck though.

    Steering box is a direct swap. Tranny and T-case I'm sure you can figure out. I think you may need a K-series tranny tunnel, but at least the 81's were still a bolt in tunnel.

    It will be a ton of work, and more involved than you think...but I understand where you're coming from. I was told to go buy a diesel Blazer cuz it was easier than swapping in a 6.2...and I didn't take that advice for much the same reasons.

    Spring under might be an alternative but you'll need a D44 front from a Wagoneer (FSJ) or J series Jeep pick-up. The perches are cast into the pumpkin on the D44 so it's pretty hard to do the swap using a Chev D44 or 10 bolt.

    You shouldn't have any trouble gaining an inch or two and still be able to tow the 5th wheel. The extra inch or two will give the spring a bit more room to work well enough to give you the ride you want.

    Rene
     
  3. 84CUCV

    84CUCV 3/4 ton status Premium Member

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    I think it would be cheaper to just buy a complete 4x4? Mike
     
  4. arveetek

    arveetek 1/2 ton status

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    Cheaper? Maybe. As much fun? Definitely not! /forums/images/graemlins/grin.gif

    Casey
     
  5. arveetek

    arveetek 1/2 ton status

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    Thanks for the thoughts!

    I'm really not sure what I'm going to do. If it wasn't for the fact that I'm going to have to pull the motor no matter what I do, it wouldn't be so bad. The biggest obstacle is that this truck is my daily driver, so I don't really have the time to have it down while I work on it for a while.

    Decisions decisions!

    Casey
     
  6. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    Having the motor out will be a necessity when it comes to swapping crossmembers and stuff though. I hate trying to do big stuff to my daily driver...the 6.2 swap was enough fun. I was lucky my friend lent me a truck to drive while mine was down.

    Rene
     
  7. imiceman44

    imiceman44 1 ton status

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    [ QUOTE ]
    Thanks for the thoughts!

    I'm really not sure what I'm going to do. If it wasn't for the fact that I'm going to have to pull the motor no matter what I do, it wouldn't be so bad. The biggest obstacle is that this truck is my daily driver, so I don't really have the time to have it down while I work on it for a while.

    Decisions decisions!

    Casey


    [/ QUOTE ]

    Well I just replied to the same question on the 2nd gen 4x4 but for a sub.
    The cross member is a bolt on, so if you want, if you have a cherry picker, you can unbolt the motor mounts, tranny mounts, and unhook the brake lines from the cross member, lift the engine still wired and plumbed, remove the cross member and replace it. It could be done in one week end if you have all the tools needed plus the parts.
    I would definitely go that route, easier faster and it will look like factory.
    If you need any more help doing this let me know.
    /forums/images/graemlins/thumb.gif
     
  8. Leadfoot

    Leadfoot 1/2 ton status Premium Member

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    Buy a used K series and go to town.
    Basically remove the front suspension and from yours and swap in the suspension from the K series with the axle. You will have the steering box, tranny, t-case, etc. You will even have the drivelines (assuming the donor is the same wheelbase). If you can find a rig that has a blown motor and crappy body, you should be able to get it cheap and can even throw the 2WD stuff on it and re-sell it for a buck or two. I would suggest setting aside the money to have the tranny rebuild or have yours converted to 4WD. If you want to use your tranny, make sure you get a case with the correct input shaft or you will have some work to do.

    I made it sound easy, but it does take some work. Remember you are dealing with suspension, steering, and brakes so take your time and do it right. With a full donor truck you should be able to get measurments and all hardware you need. Good Luck /forums/images/graemlins/thumb.gif
     

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