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Big block/Small block V8

Discussion in 'Car Forum' started by pnarq5, Sep 26, 2005.


  1. pnarq5

    pnarq5
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    Can someone tell me the difference?
     

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  2. Z28ricer

    Z28ricer
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    The small blocks block is well .... go figure... smaller, as a result the heads are also a different size, as is the intake, and just about all of the other parts.

    They share the same rear flange (for transmission) and well, they're both made by chevy of course, not too much else in common.
     

  3. DaisyCutter

    DaisyCutter
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    Imagine that you have a wad of cookie dough, we'll call it a block.

    Now you want to cut 8 cookies out of it. So you cut your cookies and they taste good.



    Later on, you decide that you want some more cookies, BIGGER cookies. So you get another block and begin to cut 8 big cookies. After you cut the first few cookies, you realize that there's now way to cut-out 8 big cookies without a bigger BLOCK.

    The size of the block is determined by the size and number of the holes/cylinders you put in it.

    This is why 454ci, 440ci, 455ci, 500ci, 460ci, etc., engines need a "big" block... While 302ci, 305ci, 350ci, 351ci, 360ci, etc. can use a "small" block.
     
  4. DaisyCutter

    DaisyCutter
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    Also, big blocks don't utilize internal combustion the same way that small blocks do... In a big block it's the weight of the gasoline that pushes the pistons down.
     
  5. pnarq5

    pnarq5
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    Is it all about displacement? Can you have a small block with a larger displacement than a big block?
    If it is all about displcement, where is the cut off between the two? Over what size does a small block become a big block.
    DaisyCutter, thanks, now I am hungry for some cookies.
     
  6. knightkrawler00

    knightkrawler00
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    Displacement isn't what seperates the big block from the small block. From the factory, in cars, the small block came in sizes from 265 to 400 and the big block came in sizes from 396 to 496. Aftermarket components can raise the displacement of the small block to 454 cubic inches and the big block to over 700 cubic inches. This is done by changing the bore and stroke of the engine, allowing bigger pistons to move further within the cylinder. A small block can't bocome a big block since the terms refers to the physical dimensions of the block itself, dispacement refers to the amount of water that can be fit into the cylinder with the piston sitting at the very bottom of its stroke.

    Hope this helps.
     
  7. David N.

    David N.
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    No, its about the physical size of the block. For example, the Ford FE series big block came from the factory with displacements ranging from 332ci to 428ci. Modern versions can be taken up to 532ci. Ford's Windsor family small block (302, 351) can be taken up to 427ci or more. A big block will usually have larger bore spacing and can have a longer stroke, so it's largest possible displacement will be greater than a small block's, but there is a lot of overlap in the actual displacements.

    Edited to put back numbers that magically disappeared.
     
  8. pnarq5

    pnarq5
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    Got it! Thanks yall for all the info. That one was buggin me for a while.
     
  9. David N.

    David N.
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    Really? How much does a piston weigh? And what about the connecting rod, and crankshaft, and other parts that must be moved to "push the pistons down?" And what about the friction that must be overcome? Now how much does a gallon of gas weigh? And how many times will that single gallon of gas have to "push the pistons down" before it is gone?
     
  10. DaisyCutter

    DaisyCutter
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    It's a joke, since big blocks don't generally get gas mileage exceeding single digits.
     
  11. David N.

    David N.
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    I didn't think you could really be serious, but you've got to learn to use smilies. Just a single one somewhere below the post and it would have been the funniest post of the week. But like it was, it shocked me so bad I almost believed it was true for a couple seconds. ;G
     
  12. DaisyCutter

    DaisyCutter
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  13. Asha'man

    Asha'man
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    eat the eat!

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    If it's strictly by block size, you could almost call the Ford modulars "big blocks". Ever see a 4.6 next to a 5.0? It's huge! 5.4 is probably even bigger, although I don't have much experience with those. And that's only 281ci and 331ci, respectively.

    Brian
     
  14. streeter69

    streeter69
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    This is Kewl

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    It is not about block size. Olds and pontiac had the 455 which used the same heads as the 350.
    Fords have the Windsor blocks, clevland blocks, FE, Lima, modifieds, modulars;g
     
  15. DaisyCutter

    DaisyCutter
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    Maybe I'll try a different metaphor...

    A big Ahole will nit-pic a simple explanation and cite specifics that don't apply to the generalization.

    A small Ahole would offer some value added explanation of their own versus agruing with everyone elses.

    :)
     
  16. David N.

    David N.
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    The modular is pretty close to the FE in size. Click on the link for a sketch comparing the FE, 351 (Windsor, I think), and a DOHC modular. (Evidently it isn't there anymore, so see the attachment. Hopefully its fairly accurate.)

    http://www.erareplicas.com/427/3pro_front.gif

    I don't think the DOHC modular is any wider than the SOHC, but I think it is taller. I'm pretty sure this is the 4.6, and I don't know how the 5.4 would compare. While Chevy is going for BB displacement in a SB package, Ford goes for SB displacement and BB size. ;g I still like my 281, though. Just wish it was a later version.
     
  17. Asha'man

    Asha'man
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    eat the eat!

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    Good sketch. I have a photo somewhere on my comp of a 4.6 and a 5.0 on stands next to each other, I'll dig it up if I have time in the next few days.

    Brian
     
  18. streeter69

    streeter69
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    This is Kewl

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  19. SJRTX

    SJRTX
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    Talking about modulars-the blocks arent all that big-especially compared to a Ford or Chevy big block. Ive carried a few 4.6L blocks around-they arent that big. Its the heads that make them look big, and the SOHC heads arent that large, its the DOHC heads that are super wide because of both cams in each head. But other than the wide heads, the blocks arent that big. And there is not really any difference between the SOHC modulars and the DOHC modulars, infact, all the parts will interchange.