blazer newbie here

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Bbs383ci, Oct 16, 2020.

  1. Bbs383ci

    Bbs383ci Registered Member Premium Member

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    hi guys,

    i just purchased and received a 1975 blazer, it seems to be in really great shape and a blast to drive.

    i do have a question on 4wd. Mine does not have locking hubs so is it AWD?

    also the high and low selector, i cannot seem to get it into low range, it will slide into high range but its still hard to tell if it has actually engaged. is there a trick to help get it into low range.

    will try to upload pictures later tonight

    thanks.

    dustin williams
     
  2. Bent77

    Bent77 lil meanie Staff Member Moderator GMOTM Winner

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    Hey Dustin, welcome aboard.

    Yours is a NP203 most likely, with just a cover on place of the locking hubs? there is a drive slug in there if that’s the case

    I’m not much help on the shifter, but others should be able to help you out there
     
  3. Wes Harden

    Wes Harden 1/2 ton status Premium Member

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    Yeah they can be a pain to get in low or low lock. The shift linkage could be out of adjustment also. There are a couple of threads that discribe the shift linkage adjustment, search np203. Your truck is an Automatic trans ?
     
  4. Bbs383ci

    Bbs383ci Registered Member Premium Member

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    Yes sir it’s automatic.

    E7907EC5-92EF-4975-A34B-9C983C453715.jpeg

    ED8661C6-AB79-4F02-A471-06501251DC1A.jpeg

    030FF313-0B17-4419-8788-DDEA1C1F7A86.jpeg

    CF587C9F-A9A1-427A-B136-13E86CD5E05B.jpeg
     
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  5. nvrenuf

    nvrenuf I grind my welds. Premium Member GMOTM Winner

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    Nice looking Blazer, welcome aboard! :thumb:

    It's not AWD in the modern vehicle sense but it is "full time four wheel drive". I've never had a full time truck so I'm not super good on the details but the idea is that it is always in 4wd (no "inconvenience" of getting out to lock hubs). Because there's a differential like device in the transfer case in "HI" or "LO" the whole drivetrain will act like an open differential (least amount of traction wins), this is what allows it to drive on the street without binding up. If you need true 4wd function then you'd use "HI LOC" or "LO LOC" which will lock the diff in the transfer case making it act like a typical 4wd truck with locking hubs. Of course, don't use the "LOC" positions on pavement.

    I'm sure there's more to it than that but that should give you a good idea of what you're working with.
     
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  6. Wes Harden

    Wes Harden 1/2 ton status Premium Member

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    So the back ground cars in pics are yours too ? Nice looking Blazer still have the 400 sbc ? The Automatic in those years came with np203. Being 45 years old anything could have been changed. The T case may have been converted to part time.
     
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  7. Bbs383ci

    Bbs383ci Registered Member Premium Member

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    thank y'all!!!

    no that is where i bought it from and it now has a 350 in it. i have contemplated building a 400 for it so it would have an original sized motor in it. This isn't something i will be going off roading in.
     
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  8. JT88K5

    JT88K5 1/2 ton status Premium Member

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    So you purchased an awesome looking lifted k5 square body 4x4 and you won’t be going off-road with it? Why not?

    So why not buy an awesome road vehicle? like Vet or Camaro?

    I can dig why you would want a K5, but that’s not the chevy I would pick if it was intended for a pavement only use.

    I’m curious as to why you picked this specific vehicle?

    OK, I can see why after reviewing the pictures.

    She’s very attractive and hard to stop staring at.
    Congratulations
     
  9. Bbs383ci

    Bbs383ci Registered Member Premium Member

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    Thank you!!

    I bought it so me and the family can cruise around in it.
     
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  10. Joel Wilson

    Joel Wilson Registered Member Premium Member

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    Welcome Dustin. I have a 77 Jimmy with a 400 and used to have full time 4wd. I have Warn hubs and a part time kit but I can drive it with the hubs locked as long as I don't have the T case in Hi lock or Low lock. If I drive it with the hubs in free mode I get better mileage and a bit more on the top end but I end up spending quite a bit of time down in the creek because of my job so I just leave the hubs locked. Then if I need the extra traction, I just pull back and put it in 4 lock. What I would do for starters, is the change the T case fluid and replace it with the same kind of fluid that came out of it. I've heard all kinds of mixtures used. On your engine, find the casting number on the block. The one that will give you the displacement is top rear of the block on the driver''s side. If you can't get to it then you should be able to tell by the harmonic balancer. 350's had a smooth edge while the 400 had a recessed or scalloped edge. http://www.chuckschevytruckpages.com/casting.html

    I was told that the engine in the Jimmy was a 350 and when I went to rebuild it, I am so damn glad that I measured the bore to make sure otherwise, I would have bought a kit for a 350 instead of a 400. The heads don't matter. You can have 350 heads drilled for 400 steam holes and be good to go. And you can get over 500 ft lbs of torque out of a 400 pretty easy.

    Joel
    norcal
     
  11. Bbs383ci

    Bbs383ci Registered Member Premium Member

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    Joel,

    i will have to look and see what it says. Thanks for the info.

    i am also going to be swapping the carb for fuel injection system and installing a 4l60e. Looking at Holleys sniper efi system. Hoping this system will help fuel mileage which right now is 8.5mpg. The carb needs to be tuned but i havent had time to mess with it being on a shutdown at work.
     
  12. 500$k5

    500$k5 wallet under gas pedal Premium Member GMOTM Winner

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    Like was said. 400 sbc's have a cutout on the balancer. 20201029_090620.jpg
     
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  13. 500$k5

    500$k5 wallet under gas pedal Premium Member GMOTM Winner

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    The 400's also have lumps cast into the block, to allow for the larger bore. These lumps aren't on any other small block. 20201029_091043.jpg
     
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  14. Bbs383ci

    Bbs383ci Registered Member Premium Member

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    I’ll take a look at it tomorrow. Would be nice if it’s the original motor but was told it was a crate engine.

    it does have 3.73 gears. Did the calculating for gearing and to get it back close to original with 35” tires would be 4.56’s but that would put me at 3238rpm @ 70mph.

    Going to show how little I know about 4 wheel drives but what is the rubber tubing coming from my differentials for, vent?
     
  15. TJ1978

    TJ1978 1/2 ton status Premium Member

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    I’d get new wheels and tires...
    Welcome aboard by the way...
     
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  16. Wes Harden

    Wes Harden 1/2 ton status Premium Member

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    Yes that is the vent. 4.10s or if available 4.33 would be a compromise.
     
  17. DB Cooper

    DB Cooper Registered Member Premium Member

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    If you install the 4l60 that you mentioned earlier, your rpm at 70 would be be right around 2200. If you did install the 4l60 without the regearing you will be hunting between 3rd od.


     
  18. ramack

    ramack 1/2 ton status Premium Member

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    Welcome to the family!
     
  19. Bbs383ci

    Bbs383ci Registered Member Premium Member

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    Thank yall!!

    the wheels getting changed are way down the road. When they do get changed it will be for 15" wheels. Not a big fan of the lower profile tires. Im working on the wife now about the 4l60, i dont think its going to be a hard sale since im getting 8.5mpg. plus it helps she likes to drive it.
     
  20. Wes Harden

    Wes Harden 1/2 ton status Premium Member

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    I have 700r4 33s and 4.88 big heavy burb. works good. But I am leaning toward 35's will work even better. Just need a good excuse to get new tires.:dunno:
     

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