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305 heads

Discussion in 'The Garage' started by BlackDog714, Dec 6, 2003.

  1. BlackDog714

    BlackDog714 1/2 ton status

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    Yeah yeah, I know. They are crap, but I need to get this truck running. Compression is good, so I think the valve seals are bad. I can replace the heads or have them rebuilt. So my choices are a set of Vortec's or rebuild the stockers.

    Oh, the symptoms are it smokes slightly at start up, but after 5 min it starts to smoke heavily at idle and Spy Hunter style if you drive it. Compression is 145 average on all 8 holes with the lowest being 138.

    PLEASE let me know if you think its something other than heads.
     
  2. R72K5

    R72K5 Banned

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    put new seals on and be done /forums/images/graemlins/laugh.gif

    why replace heads ? you have normal compression for stock engine
     
  3. jeremy91k1500

    jeremy91k1500 Registered Member

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    are these heads going on a 305? if so, i'd got with a 5.0 Vortec head, not your run of the mill 5.7 Vortec.

    sure you have good cranking compression, but what is leaking past the rings? do a leakdown test, that will tell you exactly where your problem is.
     
  4. 84_Chevy_K10

    84_Chevy_K10 Banned

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    [ QUOTE ]
    put new seals on and be done

    [/ QUOTE ]

    /forums/images/graemlins/thumb.gif
     
  5. BlackDog714

    BlackDog714 1/2 ton status

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    [ QUOTE ]
    put new seals on and be done /forums/images/graemlins/laugh.gif



    [/ QUOTE ]

    Cause I don't know how and I assume that if they go to a head shop, I might as well get them done all the way.
     
  6. 99firehawk

    99firehawk 1/2 ton status

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    Valve seals are easy take a lil bit of time but they arent hard.

    Here is what I would do. Pull valve cover. You will need to have a valve
    spring compressor (the type that does it with the head on the engine - not
    too expensive and at any FLAPS, or Sears). You will need to make sure the
    valve does not fall into the cylinder when you remove the valve keeper...two
    ways I know of to do this, but first, you will need to remove the rocker arm
    and rockers...simple to do with valve cover off. With rocker arm pressure
    off the valves, you will either use an air compressor tool to provide at
    least 90 psi into the spark plug hole (there are tools for this too, and not
    too expensive), or you can take clothes line cord, and stuff the cylinder
    full of it (thru the spark plug hole - BUT MAKE SURE TO KEEP THE FREE END
    OUT SO YOU CAN REMOVE THE CORD WHEN THE JOB IS DONE. This presses up on the
    valve, so when you remove the keeper, the valve may only fall a very small
    way, but not all the way into the cylinder (if that happens, you have to pul
    the head). WIth the keeper off, you simply remove the spring and valve seal
    and replace the seal with a new one, replace the spring and keeper, then
    reverse the process. I think that about covers it....anyone think of
    anything I overlooked?
    .
     
  7. k5guyva

    k5guyva 1/2 ton status

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    [ QUOTE ]
    I can replace the heads or have them rebuilt. So my choices are a set of Vortec's or rebuild the stockers.

    [/ QUOTE ]

    There are also good aftermarket heads for small blocks. Depending on what it will cost to rebuild your heads, you might get some new ones. SBC heads
     
  8. bigred81

    bigred81 1/2 ton status

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    Did you check to see if the drain back holes in the heads are pluged up because this will cause them to smoke at idle or the valve guides worn out from old age.

    James Startz
     
  9. BlackDog714

    BlackDog714 1/2 ton status

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    I havent pulled the valve cover yet...
     
  10. Thunder

    Thunder 3/4 ton status

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    [ QUOTE ]
    There are also good aftermarket heads for small blocks. Depending on what it will cost to rebuild your heads, you might get some new ones. SBC heads


    [/ QUOTE ]
    WOW! /forums/images/graemlins/eek.gif Prices on the heads on that site you listed are waaaaay out of line. Summit /jegs sells the same heads for hundreds less. Dont buy from them! Unless you are in to therwing your money away.
    As for the 305 heads just do as everybody says "Put in new seals and be done with it"

    If you want to put any money in the 305 engine it would be better spent buying a 350.
     
  11. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    When totally replacing a head , keep this in mind. 305 heads will fit a 350 ( LARGER BORE ) , but 350 heads do not always fit the 305 ( SMALLER BORE ) . Depends on size of valve, combustion chamber, etc.
     
  12. k5guyva

    k5guyva 1/2 ton status

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    Well, I was going to suggest that if you buy the heads (don't matter what the source is) that you can swap them to a 350 later.
     
  13. 84_Chevy_K10

    84_Chevy_K10 Banned

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    [ QUOTE ]
    [ QUOTE ]
    There are also good aftermarket heads for small blocks. Depending on what it will cost to rebuild your heads, you might get some new ones. SBC heads


    [/ QUOTE ]
    WOW! /forums/images/graemlins/eek.gif Prices on the heads on that site you listed are waaaaay out of line. Summit /jegs sells the same heads for hundreds less. Dont buy from them! Unless you are in to therwing your money away.

    [/ QUOTE ]

    What am I missing here? I can't seem to find a listing at all for pro-topline heads on Jeg's website, nor have I ever seen them in a catalog. Summit sells them, but nowhere near that price. $529.95 for two assembled heads is out of line?
     
  14. k5guyva

    k5guyva 1/2 ton status

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    I don't think it's out of line if you consider what it would take to have a shop rebuild a set. And on top of that these are new. Quality parts cost money.
     
  15. Thunder

    Thunder 3/4 ton status

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    OOps /forums/images/graemlins/blush.gif I didn't see that was the price per pair.
    Those are pretty good prices /forums/images/graemlins/thumb.gif
    Anyone ever delt with comp products?
    I am looking to buy a set of World Roush heads. At 540 a pair their price cant be beat.

    As for the 305 issue if it smokes as bad as you are saying I dont think a valve job will help much. By your description it looks like you prolly have some wore out rings also. I still say start saving up for a 350. It will be money better spent. Maby look around your local wrecking yards. Many times you can pick up a running 350 for the price of a valve job.
     

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