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Dilema: 305 or 350

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Blazer83, Feb 15, 2002.

  1. Blazer83

    Blazer83 Registered Member

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    Looking for advice: Buying a remanufactured long block, or rebuild the motor? My 83 K5 came stock with a 305 (which blew three weeks after I bought it because the guy who sold it to me dropped something in the motor and never said nothing about it, subsequently the motor siezed) so I bought a 350 from a buddy and rebuilt it. made a fatal mistake in the rebuild though. Took his word that the crank was good and built the motor without checking the journal diameters for trueness. Motor lasted 6 months and spun the rod bearings. My dilema now is to just say the heck with it and buy a reman long block 305 and put it back to emissions legal status, or rebuild the 350 AGAIN and have to deal with the emissions. The 350 is an early 70's casting and I don't have the necessary exhaust manifolds to install the smog pump and crap. The 350 is also bored 30 over and has small block 400 heads. The motor is prime to be built out as a 383 Stroker, but $$$ is preventing that. The truck is sitting in my driveway right now with no motor in it and two in the garage... Looking for your advice as I am unable to make up my mind on which is the lesser of the two evils. Granted I know there will be a performance hit with the 305, but I won't have the headache of the emissions.......... BTW, 350 had been dyno'd before I bought it at 300+Hp at the crank.
     
  2. txbartman

    txbartman 1/2 ton status

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    I recently replaced my 305 with an emissions legal 350. For your year, you basically need only a couple of things that aren't on all motors. One is the EGR valve. You can get an Edelbrock Performer intake manifold with EGR. Second is the AIR system. That's the pipes connected to your headers. Several vendors make headers with AIR. There are high $$ ones like Edelbrock and Thorley for $350+. But there are also some for around $200 by makes like Hedman and Hooker. You could also go to a junkyard and probably get AIR exhaust manifolds for a 350 pretty cheap.

    I would have to favor the 350. It will help in resale and in power/performance. And there are ways to keep it emissions legal without too much $$. But, you could also build a decent 305. If I were you, I would go the 350 route.

    Brian
    Check out <a target="_blank" href=http://tx85gmcguy.alloffroad.com>My Jimmy</a> with all her projects!
     
  3. mudhog

    mudhog THEGAME Staff Member Super Moderator

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    go with the 350 if not you will regret it later on[​IMG]

    wheeling pics
     
  4. Blazer83

    Blazer83 Registered Member

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    Other than the EGR and the AIR system (which I knew I needed for the 305 anyway), what else do I need to be concerned about? I would love to keep the 350, if for nothing else but the raw power of it, but with these new emissions tests being put into place here in Harris County,TX I am not sure I have the expertise in engine building to make it emissions legal.

    TX85gmcguy: Did you do a crate motor from GM or something else?
     
  5. 84_Chevy_K10

    84_Chevy_K10 Banned

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    I have a 305 with more power than a Vortec 350 and I would never do this again. Build a 350. Cheaper, more MPG, more power.

    Tim
    '84 Chevy K10, lifted, loud, fast, and 3/4 ton axles
     
  6. Blazer83

    Blazer83 Registered Member

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    Are you sure that is more MPG and not more Gallons per mile..........:)
     
  7. shoeless

    shoeless Registered Member

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    I feel your pain man. I'm moving back to Montgomery county this summer, and we're getting the new $40 test next year, I'm not looking forward to that. I am a state inspector, up here in College Station. Basically you need all the smog equipment that came on the truck. EGR and AIR are required for your truck(don't forget the charcoal canister), the cat is required on '84 and newer vehicles. If you look at the inspection book, the cat does not become part of the emissions system until '84, so technically it can be left off of your truck. Once you are done, tune it up very well, and pray it passes the smog test. Either way(305 or 350), you are going to have to the same things. I believe the AIR type exhaust manifolds off a 305 will fit a 350. There should not be any reason for a mildly built 350 not to pass the test, as long as you don't get too radical with it.
    Hope that helps.

    Shoeless
    '88 K5
     
  8. Blazer83

    Blazer83 Registered Member

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    Thanks guys. I appreciate all the advice. With the truck in it's present configuration, 6" suspension lift, 35" Super Swampers, I think I am better off with the 350. Gonna do it this time by the book,,,, one step at a time...... Thanks for all the help

    You guys have always been there for me when I needed the advice or help.
     
  9. BorregoK5

    BorregoK5 1/2 ton status

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    Definately go with the 350, heck you could just get a nice crank to replace the one thats bad. As far as smog is concerned, you'll probably pass if they test it as a 350's added torque will probably help push those tires a bit easier. I just passed as a 350ci with a 415ci, I wouldn't worry about the 350 passing as a 305. Good luck.

    I started with nothing and I still have most of that left! - <a target="_blank" href=http://community.webshots.com/user/borregok5> Pictures</a>
     
  10. chvyhs

    chvyhs 1/2 ton status

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    If you don't rebuild the 350 you'll always be wondering if you're getting all the power out of the 305 that you would have got from the 350.

    <a target="_blank" href=http://community.webshots.com/user/chvyhs>WebShot Pics</a>
    It's a wheelbase thing, you wouldn't understand.
     
  11. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    All of your smog equipment from the 305 will fit the 350. As long as you don't tell the smog inspector that you have a 350 he will never know unless he has a reason to check your block number. Just don't give him any reason to check it and you should be fine.
     
  12. smartpatrol

    smartpatrol Registered Member

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    Then again there is the argument why not go with a 454 or larger engine in effect you are building an engine from a core anyway. Pick up an engine in the junk yard for $100 and go at it. from what i have seen so far all the emissions fro gm vehicles are largely the same.

    I thought my Computer hobby was expensive......
     
  13. K10ANDYKHAMNIC

    K10ANDYKHAMNIC 1/2 ton status

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    oh come on now .....dont like your 305 ?? mine takes me up sand dam and comp hill and anywhere else i want to go ... :)&gt;

    pics page
    <a target="_blank" href=http://www.imagestation.com/album/pictures.html?id=4292257869&show_all=1&start=1>http://www.imagestation.com/album/pictures.html?id=4292257869&show_all=1&start=1</a>

    always gets me home K10 STEPSIDE
     
  14. StageZ

    StageZ Registered Member

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    I'd say if money is a prob, get a crate motor for now and take your time to build a bad ass 383 stroker... westside performance has a 350 for 1500 bucks... and throw some street legal headers on her....
     
  15. rockink5

    rockink5 1/2 ton status

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    If it was me I would go with the 350. Its legal, and lets face it, no substitute for cubic inches.

    In theory everything works
     

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