Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

Bigblock / Smallblock

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

  1. loudandproud

    loudandproud 1/2 ton status

    Joined:
    Jun 27, 2000
    Posts:
    451
    Likes Received:
    0
    Location:
    Ham Lake, Minnesota
    Whats the difference between a bigblock and a smallblock???
     
  2. riz

    riz 3/4 ton status

    Joined:
    Mar 7, 2000
    Posts:
    6,026
    Likes Received:
    0
    Location:
    Wisconsin
    Ones big and ones small. Just kidding. hahaha. Bigblocks have larger displacement ...cubic inches if you will.

    L8r,

    .Riz.
     
  3. 90K5

    90K5 1/2 ton status

    Joined:
    Jun 1, 2000
    Posts:
    3,719
    Likes Received:
    0
    Location:
    Lubbock, TX
    The 350 is a smallblock and 454 is big block. I dont know where they draw the line, 400 maybe?

    90K5
     
  4. jim82

    jim82 Registered Member

    Joined:
    Jun 27, 2000
    Posts:
    71
    Likes Received:
    0
    Location:
    Bay Area
    The 400 is a small block, but the 396 is a big block. The 400 is prettymuch a punched out 350/327. The 396 is the same block as the 454 and has more potential for cubic inches by changing bore/stroke etc. just my $.02
     
  5. loudandproud

    loudandproud 1/2 ton status

    Joined:
    Jun 27, 2000
    Posts:
    451
    Likes Received:
    0
    Location:
    Ham Lake, Minnesota
    But I've seen where it says there are 454 smallblocks, and 454 bigblocks. Whats the deal with that?
     
  6. TheBlazerKid

    TheBlazerKid 1/2 ton status

    Joined:
    Apr 26, 2000
    Posts:
    259
    Likes Received:
    0
    Location:
    Raymond, Washington
    nope, all bigblocks

    Your right I dont understand the jeep thing!?
     
  7. jim82

    jim82 Registered Member

    Joined:
    Jun 27, 2000
    Posts:
    71
    Likes Received:
    0
    Location:
    Bay Area
    Sometimies ads confuse short blocks and small blocks, just a thought..
     
  8. riz

    riz 3/4 ton status

    Joined:
    Mar 7, 2000
    Posts:
    6,026
    Likes Received:
    0
    Location:
    Wisconsin
    Good point Jim82, I was thinking the same thing.
    L8r,

    .Riz.
     
  9. nyyef

    nyyef 1/2 ton status

    Joined:
    May 16, 2000
    Posts:
    479
    Likes Received:
    0
    Location:
    Saudi Arabia
    a small block is exactly that a small block (relative to the big block of course).
    they do not have to be side by side to notice the difference.
    the small block is more compact and cannot hold a (relatively) big bore and continue to be reliable. the most striking feature is that the two center exhaust ports are next to each other as well as the overall size.
    the big block on the other hand is.....well....big. it has more meat for larger bores and is larger to accomodate longer strokes. all the exhaust ports are seperated. the size of the heads are considerably larger (for the much needed airflow for the larger displacment).
    yes there are 454 small blocks but not for the street. these are bored out and stroked to the max. they are strictly for racing, i have yet to see a 454 SB driven daily in summer heat. the largest GM ever went in a small block is 400. and many will argue that is has over heating problems due to the large bore, and water passage problems. some say its great (i personally dont think so).
    i have seen a bored and stroked 572 big block, driven daily, has a total of 89,000 miles...no problems.
    its all in the displacment. the larger it is ....the more power. with a big block you can have much more power (from displacment) use a lower compression, and a milder cam to make the motor a daily.
    one more thing, you can generally rev a small block more often and higher than a big block (less reciprocating weight).
    hope that clears some of your Qs.

    Knife.
    knife.coloradok5.com
     
  10. Emmettology 101

    Emmettology 101 3/4 ton status

    Joined:
    May 9, 2000
    Posts:
    8,126
    Likes Received:
    0
    Location:
    FL
    There are some aftermarket small blocks out there that can be bored and stroked to displacement size of the Bigblocks. A good example is the 91 or so Vette that Car and Driver had John Lingenfelter(sp?) built a few years ago that had a 427 smallblock. They used and aftermarket block that would allow such large displacement numbers through boring and stroking.



    Mike [​IMG]
    1982 GMC Jimmy - <font color=green>Emmett</font color=green>
    http://emmett.coloradok5.com
     
  11. talldogg

    talldogg 1/2 ton status

    Joined:
    Jul 26, 2000
    Posts:
    754
    Likes Received:
    0
    Location:
    San Diego, CA
    Come on guys, this is an easy one, and only Nyyef got it right! Being a Blazer fan means we need to know more than just differentials. Anyway. Bottom line, the difference is the actual PHYSICAL size of the block, displacement has nothing to do with it. There are BIG blocks with stock displacement of 366 ci through 454 ci, and SMALL blocks with 262 ci up to 400 ci. The displacement is deteremined by two MAIN things (connecting rod length and even the thickness of your head gaskets factor in). Bore and stroke. Otherwords the size of the piston and the throw of the connecting rod at which the crank spins it. This is why it is possible, with the right crank and bore to have SMALL blocks with up to 454 ci (that's the biggest displacement I've seen from a FACTORY, not aftermarket block). Two other important differences are weight and price. Big block parts are always almost twice as expensive and a complete big block can weigh up to 800 pounds! That's why it's important to plan ahead when considering a swap. That's not all, you also have to worry about having a strong enough tranny (TH 400), larger radiator, etc., etc. Good luck,
     
  12. Emmettology 101

    Emmettology 101 3/4 ton status

    Joined:
    May 9, 2000
    Posts:
    8,126
    Likes Received:
    0
    Location:
    FL
    Where did you see a 454 smallblock from the factory? Unless you are using or talking about the GM SB2 block which is what was used in the Car and Driver Vette and I believe it was designed for Nascar.

    Mike [​IMG]
    1982 GMC Jimmy - <font color=green>Emmett</font color=green>
    http://emmett.coloradok5.com
     
  13. Emmettology 101

    Emmettology 101 3/4 ton status

    Joined:
    May 9, 2000
    Posts:
    8,126
    Likes Received:
    0
    Location:
    FL
    Oh, and a bigblock only wieghs 100-150 pounds more than a smallblock.

    Mike [​IMG]
    1982 GMC Jimmy - <font color=green>Emmett</font color=green>
    http://emmett.coloradok5.com
     
  14. blazer72

    blazer72 1/2 ton status

    Joined:
    Apr 13, 2000
    Posts:
    939
    Likes Received:
    0
    Location:
    KCMO
    100 to 150lbs more I dont think so!!! all posting or listing I've seen SB castiron to BB castiron is about a 300 lbs between the two!!! by the way the bb is made in a 502 diplacment now by GM also.

    And yea the diff size not realy the Cubeic Inches!!!

    I understand the jeep thing I drive a BLAZER!!

    Ken
     
  15. Emmettology 101

    Emmettology 101 3/4 ton status

    Joined:
    May 9, 2000
    Posts:
    8,126
    Likes Received:
    0
    Location:
    FL
    I just saw in a magazine that the BB was only 150lbs heavier than a small block and I know a few guys that run small blocks and Big blocks in Pure Stocks that have said the same thing and they weigh there cars regularly.

    Mike [​IMG]
    1982 GMC Jimmy - <font color=green>Emmett</font color=green>
    http://emmett.coloradok5.com
     
  16. Emmettology 101

    Emmettology 101 3/4 ton status

    Joined:
    May 9, 2000
    Posts:
    8,126
    Likes Received:
    0
    Location:
    FL
    They have had 502's for a long time now.

    But I was wondering where this person saw a 454 smallblock from the factory.

    Mike [​IMG]
    1982 GMC Jimmy - <font color=green>Emmett</font color=green>
    http://emmett.coloradok5.com
     
  17. talldogg

    talldogg 1/2 ton status

    Joined:
    Jul 26, 2000
    Posts:
    754
    Likes Received:
    0
    Location:
    San Diego, CA
    I didn't say a FACTORY 454 smallblock, I said it is possible to bore and stroke a FACTORY small BLOCK and get 454 ci. Re-read my message. And it's been my experience that a big block is WAY heavier than a small block. I've never weighed them, but I doubt you have either. I've owned both and worked with both and the difference is tremendous. I currently have a BARE big block sitting in my garage and I needed help loading it and unloading it, and I'm a pretty big guy. I've moved COMPLETE small blocks around and I was intially surprised by how much they weigh. I did a swap on my very first car I ever owned (68 Camaro) and I was expecting a complete engine to wiegh a ton, but it (smallblock) didn't. I speak from experience not from what I've read. The other day I had to put in place a worker at Auto Zone, because he tried to tell me that Chevy never made a 302, just a 305. He almost cried....
     
  18. Emmettology 101

    Emmettology 101 3/4 ton status

    Joined:
    May 9, 2000
    Posts:
    8,126
    Likes Received:
    0
    Location:
    FL
    I apologize I did mis-read your post. But on the weight topic, I did read this the other day but I was also told this by people who have wieghed the engines. I have a few friends that race pure stock and have used both small and big blocks and they have to meet certain wieghts so they weigh there cars often and this is what they came up with.

    Mike [​IMG]
    1982 GMC Jimmy - <font color=green>Emmett</font color=green>
    http://emmett.coloradok5.com
     
  19. Shawn

    Shawn 1/2 ton status Premium Member Author

    Joined:
    Feb 17, 2000
    Posts:
    1,753
    Likes Received:
    5
    Location:
    5280'
    This got my curiosity going so I called Advance Adapters and talked to a Jim. This is what he said:

    454 weighs: 685lbs
    350 weighs: 575lbs

    difference= 110lbs

    If anyone can prove this wrong, please post back to this.

    I'm sure different displacements will always weigh less or more but this is the most bb and sb common sizes.

    Here's some other interesting info that was on their site:

    ************************************
    Chevy V8: When it comes to bellhousing bolt patterns, the small & big block Chevys are the same. (This is known as the 90 degree bolt pattern). These engines use a dowel pin alignment. The stock starter bolts to the bottom of the block except on some early blocks like the 265. (Note: These early blocks, in which the starter bolts to the bellhousing, should not be used for conversions). The flywheel can either be a 153 tooth, measuring 12-3/4” in diameter, or 168 tooth, measuring 14” in diameter. The 1985 and earlier flywheels are not interchangeable with the 1986 & later flywheels, due to a change on the flywheel crank bolt pattern and balancing. If you are using a stock GM bellhousing, make sure you have proper clearance for the flywheel. For the proper starter, GM used two different bolt patterns on the bottom of the block. The straight bolt pattern is normally used with the 153T flywheel and the offset or staggered starter bolt pattern is normally used with the 168T flywheel. Many Chevy blocks today offer both starter bolt patterns on the block. Some of our conversion bellhousings require a special GM starter nose cone. If your stock starter is interfering with our bellhousing you may need to purchase one of the following starter nose cones: GM# 1968122 (153T flywheel), & GM# 1984098 (168T flywheel). The oil pans on Chevy blocks have gone through a few changes. 1985 & earlier blocks are all the same except the dipstick access is either on the driver side or passenger side. In 1986, GM changed their gasket design to a one piece rear main seal. The earlier style oil pans will not fit the newer blocks. The computer controlled blocks in the ‘90s added oil level sensors. Pans that we manufacture do not have provisions for this sensor. Caution should be used if you plan on using a newer Chevy V6 or V8. We have seen aluminum oil pans on some of the later model blocks. This can cause a problem on conversions that require oil pan modifications. Most GM blocks used a triangular motor mount bolt pattern. Advance Adapters conversion mounts all utilize this most common mounting configuration. Some late 90’s blocks have varied from this bolt pattern. Please confirm that the block your converting has this triangular mounting pattern.
    *********************************************



    Shawn
    87 K5
    few mods
    [​IMG]
     
  20. talldogg

    talldogg 1/2 ton status

    Joined:
    Jul 26, 2000
    Posts:
    754
    Likes Received:
    0
    Location:
    San Diego, CA
    Did you ask if the engines were bare or if they both had their apporiate exhaust and intake mainfolds, etc. We're comparing engines in their same trim. Because I have dealt with both, I'm havinf a tough time believing it. I could be wrong, but that 110 pounds, seems like a ton.....
     

Share This Page