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need advise on axles & gears

Discussion in 'The Garage' started by GMC500, Dec 16, 2006.

  1. GMC500

    GMC500 1/2 ton status

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    hello all


    I have a 1986 GMC K15 and I wonder if the 1/2 tons are enough for me
    it is used in sand dunes driving and some mudding ( no rocks )
    it has 33x12.5x15 Maxxis 751 tyres on stock rally wheels and I don't plan to lift it or use bigger tyres

    here are the specs

    355 sbc
    vortec heads
    xe274 cam
    10.0:1 CR
    Edelbrock RPM Air gap Intake
    Edelbrock 1407 carb 750 cfm
    stock exhaust manifolds for now ( headers later )
    dual 2.5" exhaust with thrush mufflers :doah:

    sm465 + np205
    10 bolt axles (rear+front) with 3.08 stock gears and open carriers :(


    I know that 3.08 aren't ideal espeacially with this cam and I'am planning to upgrade to 3.73 gears

    are the 1/2 tons enough for me or should I upgrade to something bigger?
    and what gears brand do you reccommend?
    does anyone have personal experince with SUMMIT branded gears?

    your help is appreciated
    thanks

    Ahmed
     
  2. blazinzuk

    blazinzuk Buzzbox voodoo Premium Member GMOTM Winner

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    The rear 10 bolt just sucks. Go find a F*rd and pull the 9" from the rear if you want to stay half ton stuff, then just get some wheel adaptors to make it 6 lug. If you are only going to run 33s a 14b is just way to big of an axle
     
  3. jekbrown

    jekbrown I am CK5 Premium Member GMOTM Winner Author

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    If its gonna be used off road, I'd swap the rear axle out. Get a sf14b. You won't have to get any wheel adapters, and its a bolt in swap if you get it from the right rig.

    As to gears, I'd go 4.10 for 33s. If 3.73 is all you want, you could probably find a sf14b that has them stock... then all you'd have to do is change the front axle to match.

    j
     
  4. southernspeed

    southernspeed 1/2 ton status GMOTM Winner

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    Doing a search and mucho reading would save starting ANOTHER war of words over 10/12 blts vs 14/60's and 70's.:rolleyes: It all comes down to how you drive and how heavy your foot is. Many here wheel hard on half ton gear, others with bigger feet blow 14blts pulling out of their driveway!:D
     
  5. 79k20350

    79k20350 3/4 ton status

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    There are NO BOLT IN sf14 bolts as far as 6 lug goes... you can get a bolt in 8 lug, not six. I do agree though that a 14 bolt sf is the way to go.

    Id find a mid 80's 3/4 ton and steal the axles. It will be cheaper/ easier than regearing. Through your axles under and resell.
     
  6. bablazer73

    bablazer73 1/2 ton status

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    Thats what I did on one of my trucks. I bought a rusty non running 78 3/4 ton 4x4 for 400.00 and put the axles under my 76 blazer. the 4.10's were a nice change up from the 3.08's. I ended up selling enough parts off the 78 to break even for the axle's.

    The 10 bolt debate has been around this site since I first came to it. I have run 36's on the 8.5's without ever breaking one. I guess alot of it does come down to how you drive it. Most people will say 35's the max to run on 10 bolts. But if you start looking at the cost of doing gear swaps in BOTH axle's, it often is cheaper to swap in 3/4 ton axle's. Unless you can do them yourself. I can do it, but even for the cost of the gears and related parts, it was still cheaper to swap the axle's. AND the benefit of stronger axle's is ALWAYS a plus.
     
  7. jekbrown

    jekbrown I am CK5 Premium Member GMOTM Winner Author

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    I thought there were 6 lug sf14bs out there... on those, what doesn't swap over? spring perch spacing? bah... talk about easy fixes. Buy a new set of perches from a vendor here and give someone a six pack to weld them on for ya (if you don't have a welder). Its all good. :thumb:

    j
     
  8. lochenjons

    lochenjons 1/2 ton status

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    I have 3.73 gears if you wanna buy them. Came from my front d44 in a '77 blazer after I put 4.56's in it
     
  9. GMC500

    GMC500 1/2 ton status

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    hi
    I don't think that I will find a 6 lug 14bsf here ( I am from Saudi Arabia )
    I'll try to find axles from a 3/4 and 15 rims so I can reuse my tyres since they are relativly new and 15 are usualy cheaper than 16
    and it won't be hard to sell those old 1/2 tons

    thank you all for your replies

    and BTW here is a pic of my rig ( it was raining yesterday) http://www.9q9q.org/index.php?image=VflFfEOOmkKjYW


    thanks again
    Ahmed
     
    Last edited: Dec 17, 2006
  10. jekbrown

    jekbrown I am CK5 Premium Member GMOTM Winner Author

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    it does that with links... no biggie. :thumb:

    good point on not finding a relatively obscure axle... doubt there is very many good junk yards in Saudi!

    j
     

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