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Small block or Big block?

Discussion in 'Engine & Performance' started by Rex Caron, Sep 27, 2020.

  1. Wumbo

    Wumbo Full Access Member

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    820 heads will give you a bump in compression (113 cc chambers) and still flow similar to 049 and 781 heads.
     
  2. Bextreme04

    Bextreme04 Full Access Member

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    The L29 heads supposedly flow similar(some places say better) to 049 heads, but will give you some headaches on a Gen IV block. They have different cooling jackets and require a special head gasket to work on Mark IV blocks. They also need special ARP rocker studs to run an adjustable valvetrain as well as different pushrod guides. They also wont work well for carbureted applications in cold weather climates due to the absence of an exhaust crossover. You will also want to make sure that you can get a reasonable compression ratio with the pistons you have without needing to go to a crazy thick head gasket. The L29 heads have a teeny 99cc combustion chamber and the factory L29 piston is a flat top with valve reliefs. I am still waiting on main bearings to come in so I can measure my deck clearance, but I should be between 9:1 and 9.4:1 on my mild rebuilt L29. If your factory pistons have any kind of dome, they most likely wont work with L29 heads.
     
  3. Rusty Nail

    Rusty Nail Whatever!

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    Sig Erson cams kick ass and that's my choice yeah.
    So are small blocks.

    Keep driving it and let her loosen up a bit. Time for an oil change? No? Prolly not a bad idea.
     
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  4. Catbox

    Catbox Full Access Member

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    I have a set of the L-29 heads that I am thinking of replacing the peanut port heads with.
    My truck wears a set of 85-90 peanut ports on the big block and runs just fine.
    But I want more compression and the Vortec heads with my blocks stock smog style rebuilder pistons will be a great match.

    Alternatively I also have another complete L-29 454 that may or may not be rebuilt to go into the truck. If not the truck, my '54 Bel Air.

    A fuel pump now a days is simple to make happen from the tank as there are many options for either of my vehicles. I can even buy a new tank for the 66 year old car that is set up to have the in tank pumps mounted easy peasy.
     
  5. Usmczo6

    Usmczo6 Full Access Member

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    What cam are you running? How does it act?
     
  6. Catbox

    Catbox Full Access Member

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    I have not done the head swap just yet.
    Finances have to be right to drop the money on the rebuild of the heads.

    Otherwise the 454 in my truck now is just peachy.
    Runs like a top and has the coolest cam in it.
    The rebuild receipt simply states it is a "RV" cam.
    So I am sure it is just a touch more than a stock cam that would have come in that era of engine.
    But I won't know for sure until I get in there and pull every thing apart.
     
  7. Rusty Nail

    Rusty Nail Whatever!

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    "RV" cam is just as bad as having a "3/4 race" cam. .
    Lololol hahaha
     
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  8. 82sbshortbed

    82sbshortbed Get outta there! Supporting Member

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    BBC or gtfo!
     
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  9. PrairieDrifter

    PrairieDrifter Full Access Member

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    Small block every time.
     
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  10. Frankenchevy

    Frankenchevy Lying Dog-Faced Pony Soldier Supporting Member

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    OP, have you considered switching the engines from your k20 to k30. BBC goes in the k30, SBC goes in the k20. Basically free to do...
     
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  11. TubeTruck

    TubeTruck I like anything fast enough to do something stupid

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    In that thing? Definitely a 454! 8.1 swap if you don't want to upgrade the engine as the aftermarket sucks for the engine. Gen VI if you want to mod it.
     
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  12. Matt69olds

    Matt69olds Full Access Member

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    26E71FE4-BE2B-4D18-B74F-FBBF0D0E2960.jpeg 78E1B130-2A9B-4A42-97C9-55E54380E637.jpeg 78E1B130-2A9B-4A42-97C9-55E54380E637.jpeg 78E1B130-2A9B-4A42-97C9-55E54380E637.jpeg A big block will make more torque right off idle (and then the curve will start to climb!) than your small will ever make. To make big block torque with a small block means starting with a BIG small block, or forced induction.

    Big torque engines to me are much more fun to drive. Steer the front wheels with the steering wheel, the rear tires with the throttle!

    26E71FE4-BE2B-4D18-B74F-FBBF0D0E2960.jpeg
     
  13. Matt69olds

    Matt69olds Full Access Member

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    Crap! Why did those show up multiple times????
     
  14. Bextreme04

    Bextreme04 Full Access Member

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    :happy175:
     
  15. Rusty Nail

    Rusty Nail Whatever!

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    I thought you were trying to make a point?

    Thats some race car driver dude..who is it? I cant put my finger on his name but he's a badass for sure.
     
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