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Can I put a 71 block in an 85 and be legal?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by txbartman, Jul 20, 2001.

  1. txbartman

    txbartman 1/2 ton status

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    I have an 85 Jimmy with a pathetic 305. I have someone on here that has a 71 350 for sale complete. Could I take that 71 350 block attach 85 intake and exhaust manifolds to it as well as the 85 carb with all the emissions and be legal? Is there any emissions stuff that Iwould cause the block to be different? Would I also have to replace the heads? I want to keep all my emissions stuff as I don't want to deal with not passing inspection. Opinions?

    brian

    85 GMC Jimmy <a target="_blank" href=http://tx85gmcguy.alloffroad.com>tx85gmcguy.alloffroad.com</a>
     
  2. muddin4fun

    muddin4fun 3/4 ton status

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    If it can pass emissions requirments for 85, then you'll be fine. I don't think it'd be worth it. You could sink a thousand dollars in it and still not pass emissions and then you're up a creek without a paddle. I would pass.....just my .02 cents.

    I've got a mind like a . . . a . . . what's that thing called?

    <a target="_blank" href=http://www.geocities.com/muddin4fun79blazer/>http://www.geocities.com/muddin4fun79blazer/</a>
     
  3. dyeager535

    dyeager535 1 ton status Premium Member

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    If you were really willing to do the work to make a clean running motor, you can do it. Throw legality out the window, because A) almost impossible to get the same answer twice from any of the state or government agencies that handle this sort of thing, B)If you do get the same answer, when you have to get it tested, there will be a DIFFERENT answer and C)There is no way they are going to know what motor it is if you don't tell them.

    Your going to want to keep the '71 heads, the 305 heads are going to push compression way up, and are pathetic POS castings. 305 intake CAN be ok, e of the Aluminum ones off of a car would be a nice addition. (for example 80's SS's have an AL intake, I bet the non SS motors had them too) Supposed to be a decent intake, and probably would work even better on a 350 with heads that flow better.

    Like I said though, it can be a lot of work. Cat converter in good shape, not too high compression, motor in VERY good tune, the works. Any way you go on that 305 is going to be a pain to get the same performance as you can out of a stock 350. Just be ready for the hassles.

    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
     
  4. txbartman

    txbartman 1/2 ton status

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    I may just pick it up so I have a core. I have found a good shop to buy a emissions legal long block from, but I can't swap a 305 core for a 350. And the core charge is $375.

    85 GMC Jimmy <a target="_blank" href=http://tx85gmcguy.alloffroad.com>tx85gmcguy.alloffroad.com</a>
     
  5. dyeager535

    dyeager535 1 ton status Premium Member

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    Never hurts to have spares! : )



    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
     
  6. baldbandit

    baldbandit 1/2 ton status

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    Do they do tailpipe tests where you are? I'm also in Texas, and in my county, you only have to have smog pump and cats in place and appear to be functional. They do not test it at the tailpipes. 305, 350, 400, most won't even know any difference.

    baldbandit

    "Have you driven over a F@RD lately!!
     
  7. txbartman

    txbartman 1/2 ton status

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    I'm in Collin county, next to Dallas. They do all sorts of checking here, including tailpipe checks. i was thinking of heading out to Sherman or Greenville when it comes inspection time. Different counties test different things.

    85 GMC Jimmy <a target="_blank" href=http://tx85gmcguy.alloffroad.com>tx85gmcguy.alloffroad.com</a>
     

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