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Upgrading Alternator

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Josh, Jun 13, 2001.

  1. Josh

    Josh Registered Member

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    Ok guys, I have just spent some time looking through the archives for a higher output alternator swap. I found alot on the aftermarket alts but not much on factory parts. I have a '77 - 400 - with A/C. I need one with a V belt, do you guys have any suggestions, from other vehicles??

    Josh
     
  2. dyeager535

    dyeager535 1 ton status Premium Member

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    I bought an 85 amp unit at the swap meet he other day, the guy told me it was off a mid 80's Monte SS. Seems liek the wrong unit for that car, BUT....just about any Gm alternator from that time period will work. Make sure the alternator is as "thick" as yours, or else you will be fabbing brackets for it. As well, make sure all the bolt holes for mounting are the same. I have not compared enough to be sure, but I would bet most alternators form that period were the same setup bolt wise, as long as they were the same "thickness".
    In my case, the 85 amp unit is the SAME thickness as the 44 amp one on my truck now.

    On the other makes (Olds for one) you will have to "clock" the alternator to the right position, so the plug and bolts line up right, but it is easy if you are a little careful. It just involves seperating the two halves and bolting them back together in the right orientation.

    The amp rating is stamped on the distributor case, look for it and the stamped in casting or part number right next to it. For some reason, some of the rebuilt units will ahve scraped off or nonexistent ID numbers.

    I believe about 110 was the max factory alt output our style, and it was probably for a fully loaded mid 80's Cadillac.


    Dorian
    My tech/links page: <A target="_blank" HREF=http://www.dorianyeager.com/index2.html>http://www.dorianyeager.com/index2.html</A>
    No anti-theft measures on your truck? No pity when its stolen
     
  3. kpanza

    kpanza 1/2 ton status

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    The Powermaster #47294 140 Amp alternator will bolt right in! Just making sure you knew that...I have one in my '87, that alternator will replace anything from 63-87 on Chevy/GMC trucks...
     
  4. Josh

    Josh Registered Member

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    Thanks for the posts
     
  5. BurbinOR

    BurbinOR 3/4 ton status

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    Can also go aftermarket with a WranglerNW Products one - got mine - 135 amp unit with direct charge - for $250 - kicks tail running all kinds of accessories including a winch with no problem and I only have one battery (for now anyway [​IMG]).

    <font color=blue>'79 ONE TON TPI K5 - See it at---&gt;<A target="_blank" HREF=http://www.blazzinor.coloradok5.com>http://www.blazzinor.coloradok5.com</A>
     
  6. Storm Trooper

    Storm Trooper 1/2 ton status GMOTM Winner

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    Keep in mind larger cables from alt. to batt.
    Don't want to see anyone due a melt down......
    I already have full size wires from my alt. to my two batteries.

    [​IMG]<font color=red>[/b]"Rid'in HigH in my K5"[​IMG]
    ....[​IMG]<font color=blue>[/b]"6" Lift -<font color=purple>38.5's"[​IMG]....
     
  7. BurbinOR

    BurbinOR 3/4 ton status

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    Yep, thanks. Got a 1/0 wire that came with the alternator, actually thicker than my battery cables are................

    <font color=blue>'79 ONE TON TPI K5 - See it at---&gt;<A target="_blank" HREF=http://www.blazzinor.coloradok5.com>http://www.blazzinor.coloradok5.com</A>
     

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