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30 over

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by CURTIS111, Sep 5, 2000.

  1. CURTIS111

    CURTIS111 Newbie

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    A buddy of mine is trying to sell me a 350 2 bolt main bored 30 over for 70 $$$.He getting out of the fix'em ups,and buying a new Truck..has anybody had bad luck with a 350 bored 30 over..I ask because my brothers eng is bored 30 over and his truck always runs hot(not good in Arizona).I have a 79 Blazer with a stock 350..Tell me what you think?????
     
  2. Wheels

    Wheels 1/2 ton status

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    I have heard that you can go to .120 over on the 350. The only problem you will have is the thickness of the cylinder walls and the amount of corrosion that has taken place in the water jackets. Unless you have access to some pretty expensive NDI (non-destructive inspection) equipment, I wouldn't go past .060. If the water jackets are pretty crusty and rusty, then a lot of corrosion should be expected and I would pass on the block. I have mine punched to .080 over and live in Oklahoma. I plan on a stroker later on but I had some NDI work done on the engine before I went that far (got the block cheap). When you get it back from the machine shop flush the engine with water and use bristle brushes to break up the crud. Then flush, flush, flush some more. After the initial running, back flush the engine. On the hot runner, may have some crud that broke loose that is blocking the water jackets or raditor. Or it may be a timing problem.
     
  3. Jason73K5

    Jason73K5 1/2 ton status

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    You won't have any problems with a block just because it's 30 over, thats actually considered a mild overbore.
     
  4. Emmettology 101

    Emmettology 101 3/4 ton status

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    Yes, .30 is a mild overbore and some places I have seen that that makes it a 355. You shouldn't have anyporblems with that in AZ. I bet that giys cooling systems is not up to par!


    Mike [​IMG]
    See <font color=green>EMMETT</font color=green> -&gt; http://emmett.coloradok5.com
     

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