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engine opinions?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by 89Jimmy, Dec 9, 2002.

  1. 89Jimmy

    89Jimmy 1/2 ton status

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    Hello,
    I'm lookin' for opinions. It's time to re-power the '85. I've got a set of 350 vortec heads. They've got screw in studs, bosses are machined for heavier springs and over .500 lift and pc seals are installed. Chambers are 62 cc. I'm thinking about buying a NAPA 400 shortblock and installing a comp cams xe 268h, edelbrock performer rpm intake, and afterburner headers. I'm planning on keeping my accel tbi system. Is it correct that I'll have to drill holes in the heads to match the coolant holes in the 400 block? Can I just use a 400 head gasket as a locator for the hole placement? Does anyone know of any problems with this setup? I'll also need a 400 balancer and flexplate, correct? Truck is daily driver and 90% street 10% trail. Any thoughts?
    John
     
  2. 4x4Freak

    4x4Freak 1/2 ton status

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    Sounds like a good setup except I wouldnt buy a rebuilt engine from a parts store. I would call around to some machine shops and see how much they would charge to build you a short block. It might be just as much or less than one from a parts store and it would more than likely be built right. I have heard stories of engines being built with mixed and matched parts and some being bored over to their limit.
     
  3. imiceman44

    imiceman44 1 ton status

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    I would normally agree about parts stores' short blocks but NAPA is a different quality from what I have seen so Far.
     
  4. Lonnie

    Lonnie 1/2 ton status

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    Yes, you have to drill the holes to match the gasket otherwise overheating will likely result. The gasket will work as a template, but they are not perpendicular to the head surface. I can get you the particular angles, but have currently misplaced them. I will post the info when I find it.

    A 400 balancer & flywheel is required for proper balance.

    This is a good combination, but due to the small combustion chamber of the heads, your compression may be too high depending on piston type.
    Lonnie
    Lonnies Performance Automotive
     
  5. 89Jimmy

    89Jimmy 1/2 ton status

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    The only reason I'm looking at a parts store short block is because rebuildable 400 ci. cores seem to be scarce in this neck o' the woods. I've looked at several that were boat anchors. I'd like to rebuild one so I could get the c.r. that I want. I'd like to make some power on 87 octane.
    John
     
  6. unsane

    unsane Guest

    Why not just build a Stroker???
     
  7. Blazerfun

    Blazerfun Registered Member

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    The 400 block with its siamesed cylinders was not the greatest of designs and was not kept around long because of the overheating and cracked block problems the engine had. It makes a great alchahol or methanol motor, but for street driving you would be better off getting a .030 or .040 over 350 short block from a reputable machine shop. With those small chamber heads and them being cast iron, be watchful of pre-ignition. I would suggest a thick head gasket and no more than a 9:1 CP gross...before the gasket. With aluminum heads you could get away with a 10:1 with a steel shim type head gasket and 87 octane!! /forums/images/graemlins/cool.gif Hope this all helps some.
     
  8. Klink K5

    Klink K5 1/2 ton status

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    I would not buy a napa short block if my life depended on it. As a mechanic, i've seen napas engines up close and they do some wierd rebuilding procedures such as bore one hole .020 and the next .040 . Thats all I'm saying. I have several 400's for parts if you are looking for a good flywheel and balancer, I have what your looking for. Also, I have a stock 400 crank that needs to be turned .010 out of a 71 400. Also have block if really intrested. PM me if your intrested /forums/images/graemlins/thumb.gif
     
  9. dyeager535

    dyeager535 1 ton status Premium Member

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    I think if you check GM's older service manuals, you will find that even new, boring each cylinder out to different sizes was done. So were oversize lifters, etc.

    I'm not saying I'd want an engine with a .020 over and .040 over cylinders, just that it may not be a big deal for low performance engines.
     
  10. imiceman44

    imiceman44 1 ton status

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    I second that.
    I always liked the power I could get from more cubes, but the way they got 400 out of this one eliminated water passages and made it overheat a lot.
    In my truck I want an engine that can run cool all the time no matter what happens not the opposite.
    /forums/images/graemlins/thumb.gif
     

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