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How to identify common engines

Discussion in 'The Garage' started by 84gmcjimmy, Apr 7, 2005.

  1. 84gmcjimmy

    84gmcjimmy 1 ton status

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    How can you tell apart the 305, 350, 454, and other common, stock engines in chevy or GM trucks?
    I realize there would be size difference between the 305 and the 454...but...
    How can I tell each engine apart? Is there numbers someone accessable to see? Or can anyone give me tips?
     
  2. 1979jimmy350

    1979jimmy350 1/2 ton status

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    the difference between the big and small block is easy. Look at the exaust and the valve covers. The exaust will have four seperat ports spaced out unlike the small block where the middle two are right next to each other. The valve covers are also a lot wider. For telling the difference between a 305 and a 350 you will have to go by casting numbers
     
  3. RustBuket

    RustBuket 1/2 ton status

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    The 400 is externally balanced so the harmonic balancer has a balacing peice inside. And some of them have 3 freeze plugs on each side. However, some don't.
     
  4. dirtwarrior17

    dirtwarrior17 Banned

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    a 305 and a 350 are the same block just different bores and strokes... you can see the difference just in the size between an sbc and a bbc not to mention the exhaust ports, but to tell between a 305 and a 350 you'd have to look for the numbers on the tag to tell you.

    also a bbc and sbc sound different.
     
    Last edited: Apr 8, 2005
  5. Cricket

    Cricket 3/4 ton status

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    From page 14 of David Vizzard's book, How To Rebuild Your Smallblock Chevy. Just so you know Steve this is only for smallblock displacement up to 400ci

    "The best way to identify a block casting when hunting for a specific one is by the block casting number. This is normally located in two areas; on the flywheel flange at the back of the block on the right side when viewed from the front of the engine, or in the area directly beneath the cam sprocket. Of course that's not an easy one to read when the block is together so the one on the back of the block is the one to check. However, there are some ways of roughly identifying what you are looking for without having to store a whole batch of engine numbers in your mind. If the engine is out of the vehicle, you can establish whether or not the engine is pre-68 or 68' and later engine by looking at the crankshaft flange where the flywheel or torque converter plate bolts on. If it is a small counterweighted type flange, it's a 68" or later engine. If it's a plain round diameter, it's a pre-68 engine. Of course this won't actually tell you the displacement, but it will establish whether it has small or big bearings. As far as 400 cid blocks are concerned, you can tell a 4 bolt block from a 2 bolter by the number of freeze plugs on the side of the engine. Three freeze plugs along the side indicate the block is a 400 with four bolt main caps. Two freeze plugs indicate a two bolt unit. To pinpoint blocks any further than this, you'll need to check the block casting numbers."
     
  6. 84gmcjimmy

    84gmcjimmy 1 ton status

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    Alright thanks guys. I'm going away for the weekend, so I will aask more quesions monday.
    Thanks :)
     
  7. Thunder

    Thunder 3/4 ton status

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  8. Emmettology 101

    Emmettology 101 3/4 ton status

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    One thing to add. On the '87+ SBC's, you can look at the back of the block on the bellhousing lip. On the drivers side(or was it passenger side) there will either be a 5.0L or 5.7L..... :thumb:
     
  9. R72K5

    R72K5 Banned

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    telling between such engines as 283,307,327
    and 305 and 350

    are the most diffcult without decoding either casting code on back or the suffix stamping code on front deck pad(i always go by this one since it tells year make model HP carb and mains) at nastyz28.com decoding site

    you really dont know for sure less you run the numbers,

    on BBC's the hardest would probably be between 396 and 402 id say
     
  10. PhoenixZorn

    PhoenixZorn 1/2 ton status

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    I've heard, but not verified, that there is a visible difference between a 327 and a 305... maybe the external balancing or something, but that's what I've heard.

    The other engines, I'd have to agree... casting numbers tell all... and while the mechs thought my old engine was a 327 because of the external differences, they weren't sure until the engine was out of the truck.
     
  11. Z3PR

    Z3PR Banned

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    If I remember correct the 305 and 350 use different harmonic balancers. One is thicker then the others.
     
  12. kgblazerfive

    kgblazerfive keymaster Premium Member GMOTM Winner

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    Depends on the years I have a 307 that has a huge balancer and a 350 that I would swear is a 283 by the size of the balencer.The only small block that you can determine what it is from the balancer is the 400 because it will have balance groves cut in it, because its externally balanced. Same with 454.
     
  13. 84gmcjimmy

    84gmcjimmy 1 ton status

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    Alright I will just go by the numbers stamped on them.
    I will also read on that website someone posted.
    Thanks
     
  14. 1985K20

    1985K20 1/2 ton status

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    look up for casting numbers, usually behind passenger side cylinder head on top of housing.

    Numbers usually have 7 digits,find it, write it down then refer to a website like mortec.com and BING you know the guy is trying to sell you a suppose to be 350 sbc when its a 305 ;)
     
  15. 1985K20

    1985K20 1/2 ton status

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    driver side head.... :blush:
     

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