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bbc 396,454?

Discussion in 'The Hokey Ass Message Board' started by patrick english, Jul 29, 2013.

  1. patrick english
    Joined: Feb 15, 2008
    Posts: 806

    patrick english
    Member
    from La puente

    What is the difference in the bbc oval port and square port heads?(besides the shape).

    Are both style heads compatible with a 396 block?
     
  2. blowby
    Joined: Dec 27, 2012
    Posts: 6,858

    blowby
    Member
    from Nicasio Ca

    Valve size.

    Both were available on the 396.
     
  3. MATACONCEPTS
    Joined: Aug 7, 2009
    Posts: 2,069

    MATACONCEPTS
    BANNED

    Oval port are better street driving. Some say better performance. Rectangular is suppose to be better but is more true like in BIG drag racing stuff.

    All BBC are compatable. There's Tall Block Stuff to stay away from.
     
  4. 32-3 WINDOW
    Joined: Nov 23, 2005
    Posts: 1,696

    32-3 WINDOW
    Member
    from utah

    there is also open chamber or closed chamber , referring to the combustion chamber
     

  5. blowby
    Joined: Dec 27, 2012
    Posts: 6,858

    blowby
    Member
    from Nicasio Ca


    Yes, and oval and square port were made in either open or closed. Match to pistons for compression ratio. Original 396 were closed.
     
  6. I have a set of oval port heads with Manley Valves, Springs and guides available. these are the 336781 heads, considered the best of the oval ports (along with the 049). Open chambers and 2.18/1.888 valves. PM me if you need em.
    Car Craft made 589 HP and 550 Ft Lbs using a set of these Oval Ports with just a little back cut on the pocket and larger valves.
     
  7. BOBCRMAN
    Joined: Nov 10, 2005
    Posts: 846

    BOBCRMAN
    Member
    from Holly

    Are both style heads compatible with a 396 block?

    Compatible... Not really. All will bolt on. But putting a set of 122 cc. open chamber oval ports on a 396 will result in a gutless, gas guzzling TURD!

    You would need the early small closed chamber heads 95-97 cc. To get any power. As mentioned ^^ oval port for 396 street motor. Hard to make a powerful 396 as most of the go fast stuff is based on a 4.25" bore 427 up block. :D
     
  8. kyvetteman
    Joined: May 13, 2012
    Posts: 760

    kyvetteman
    Member

    Chevy managed to squeeze 425 hp out of a 396 in the '65 Corvette using the first Mark IV square-port head, casting #3856208. These heads had a 109 cc combustion chambers and 2.19/1.72 valves. Very rare and one year/application only. Pricey too, if you could find them.
     
  9. trbomax
    Joined: Apr 19, 2012
    Posts: 289

    trbomax
    Member

    #3856208 - 106.9 cc,2.19/1.72 valves,396/427-'65-'67,425hp 396-427. I have 4 sets.
     
  10. kyvetteman
    Joined: May 13, 2012
    Posts: 760

    kyvetteman
    Member

    Have I seen you on hoarders? :rolleyes:

    I was referring to the 'vette application. They may have been used on other engines.
     
  11. trbomax
    Joined: Apr 19, 2012
    Posts: 289

    trbomax
    Member

     
    Last edited: Jul 29, 2013
  12. Velocity is the main difference to be concerned about. Assuming you have the proper open/closed chamber head to match your pistons--/// the rectangle ports are a high rpm head and the ovals have smaller runners that keep velocity up at lower rpm. Much better for street rpm/torque.


    Posted using the Full Custom H.A.M.B. App!
     
  13. kyvetteman
    Joined: May 13, 2012
    Posts: 760

    kyvetteman
    Member

     
  14. gold03
    Joined: Oct 11, 2009
    Posts: 84

    gold03
    Member

    Don't be afraid of tall block BBC. You just gotta let me know and I will gladly take them off your hands.

    Once you know how there are some big advantages.
     

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