Identify this SBC block
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Identify this SBC block

  1. #1
    Senior Member Delemorte's Avatar
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    Default Identify this SBC block

    So my motor is coming apart and Warp mentioned my block may not be a 350 at and could be a 327 (I wont mention his reasoning as to not bias the pool)... 10 internet cool points to who ever confirms WTF this is... :-)

    Heads are world heads. I just want to know what the short block is..

    Casting numbers

    18GM
    3956618










    Quote Originally Posted by jetboatperformance View Post
    the ensueing fire would likely be extinguished by the sinking however

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  3. #2
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    Years Casting CID Low Power High Power Main Caps Comments
    1969 3956618 302 290 290 4 Z28
    1969 3956618 327 235 235 2 fullsize
    1969 3956618 350 250 350 2/4 cars

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    Senior Member Delemorte's Avatar
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    Quote Originally Posted by Sangster View Post
    Years Casting CID Low Power High Power Main Caps Comments
    1969 3956618 302 290 290 4 Z28
    1969 3956618 327 235 235 2 fullsize
    1969 3956618 350 250 350 2/4 cars

    And i have all that info.. so which one is it? 327 or 350?
    Quote Originally Posted by jetboatperformance View Post
    the ensueing fire would likely be extinguished by the sinking however

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    Senior Member gregb's Avatar
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    With the pistons that it has it's a 350. (L2256F is a 350 piston)

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    New here Beer:30's Avatar
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    Wow. Haven't seen rubber/cork intake-valley front/rear gaskets in a LONG time.
    Quote Originally Posted by gn7 View Post
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    Senior Member ap67et10's Avatar
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    if i remember right there a few ways to know if its a 327. the earlier ones were easier to tell the differences. I believe that all 327 cranks were never drilled for a damper bolt, they have pressed on harmonic dampers. I do remember when i had mine that i drilled it, so if it has a bolt, it doesn't mean its not a 327 crank. the other thing that i remember is that the mounting flange for the flex plate is different. the 327 cranks have really rounded edges where a 350 crank tends to have squarer edges on the mounting area for the flexplate. From what i know there is almost no way to tell, by the block (on the later ones, but could be wrong) or anything other than the crank and pistons. should have a different compression height to compensate for the stroke. (again, i'm going off memory here)

    AP

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    Senior Member Delemorte's Avatar
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    Quote Originally Posted by gregb View Post
    With the pistons that it has it's a 350. (L2256F is a 350 piston)

    Yes it does. I was just curious as to what this block started life as... and if im reading this right they are pretty similar so i probably wont be able to tell...
    Quote Originally Posted by jetboatperformance View Post
    the ensueing fire would likely be extinguished by the sinking however

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    Village Idiot fc-Pilot's Avatar
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    GM went away front the fully enclosed distributor "thingy" right around that era that the 350 came out. If I remember correctly only the 1968 327 had large main journals (but don't quote me on that). The last 327 I built was a 68 large journal that did "NOT" cave the enclosed distributor. On a side note, did the big journal 327's come with four bolt mains? The one I did was a two bolt out of a Vette.

    Paul

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    Cantard 71hallett's Avatar
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    Quote Originally Posted by fc-Pilot View Post
    GM went away front the fully enclosed distributor "thingy" right around that era that the 350 came out. If I remember correctly only the 1968 327 had large main journals (but don't quote me on that). The last 327 I built was a 68 large journal that did "NOT" cave the enclosed distributor. On a side note, did the big journal 327's come with four bolt mains? The one I did was a two bolt out of a Vette.

    Paul
    There are some 4 bolts out there but not many.

  12. #10
    New here Beer:30's Avatar
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    I've had ALOT of 327s and none have been 4 bolts. I don't know if there were ever any from the factory, but that can be changed easily enough - these days.

    Same with the crank bolt. The 327 in my '56 BelAir - I had drilled just to help keep the FluidDamper on. It was about to leave the engine builder and I reminded him I wanted a crank bolt. His guy ran over with a drill and tap and knocked it out right there. Took 5 minutes.

    So, don't always trust the non-crank-bolt-being-a-327 thing.
    Quote Originally Posted by gn7 View Post
    EFI is the wave of the future. There can be no denying it. Electronics have been on the leading edge of our entire lives. Not only os the magneto dead, but the standard issue CDI is wavering. Its all about total fuel, air AND spark control. Anybody that thinks its not has their head up their ass.


    2001 SleekCraft 30' Heritage SSB, open-bow mid-cuddy. 496HO / Bravo-I.

  13. #11
    What the Hell is That? 72Hondo's Avatar
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    I have a 327 block I believe mine was converted to a 4 bolt Studded though.
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    Senior Member GT Jets's Avatar
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    GM's first gen 350 used a 327 block, there was no identifying traits as to which were which.

    There are four bolt 327's. Rare but they exist.

    If I was to bet, I would say an early 350..

    GT
    GT


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  15. #13
    Senior Member Hydroguy's Avatar
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    It's a 350. simple enough. No if's ands or buts

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