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Question for you BBC guys

Discussion in 'The Garage' started by tiger9297, Jul 22, 2006.

  1. tiger9297

    tiger9297 1/2 ton status

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    I have an opportunity to buy a BBC from a friend of mine who owns his own shop (468ci). He told me he has numerous BBC heads and I can basically pick the ones I want. I was planning on getting the casting numbers of the heads so I can see exactly what I'm getting. Do any of you have a link to a site where I can enter the casting numbers and get the specs. on the head? Ideas??

    Also, I would like to put a serpentine setup on this engine (it' would go in my '90 K5). I see these kits for SBC's but not for BBC's. I have all the accessories I just need the brackets. Should I just go to the dealership and buy the individual brackets for an early 90's 454?
     
    Last edited: Jul 22, 2006
  2. ryoken

    ryoken Puppy Fabricator Premium Member GMOTM Winner

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  3. tiger9297

    tiger9297 1/2 ton status

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    Thanks. Thats a great link. TONS of info.

    Anyone got any ideas on the accessory brackets?
     
  4. nvrenuf

    nvrenuf NONE shall pass! Premium Member

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    I dont think there are kits offered for a bbc, you'll probably have to look in a salvage yard for something in the mid 90's.

    As for heads I think most people will agree that the best heads to use will have casting numbers ending in "781" or "049". These are nearly identical so either would work great.
     
  5. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    781's are the best head of choice. The only thing that will make them better is to install the larger valves so they will breathe better and have slightly more flow. :thumb:
     
  6. tiger9297

    tiger9297 1/2 ton status

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    How would these heads compare to the L29 Vortecs?
     
  7. nvrenuf

    nvrenuf NONE shall pass! Premium Member

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    better
     
  8. tiger9297

    tiger9297 1/2 ton status

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    Edit: Few more questions

    Is a 496 just a 454 w/ a 4.37" stroke? Do you have to machine the block for clearance like you would when building a 383?

    Is it worth buying aftermarket heads for a BBC or just stick w/ stock? They are $$$$$$$$$!!!

    Is 8.5:1 CR high for a BBC. Seems like most "built" SBC's that run on pump gas are low 9's. Maybe its just the ones I've seen but seems like most BBC's are mid 8's?

    Which would you rather have:

    MPFI 383 w/ Vortec heads

    or

    MPFI 454 w/ stock heads and a cam?
     
  9. SkysTheLimit

    SkysTheLimit 1/2 ton status

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    A 496 is a bored & stroked 454. I don't know if you have to machine the block tho. I will find out if mine was since you got me curious now.
     
  10. BadBob

    BadBob 1/2 ton status

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  11. DEMON44

    DEMON44 Low-Tech Redneck

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    Traditionally a 496cid is your 454 bored +0.060" (4.310") and crank stroked +0.250" (4.250")

    I'll take a 454 over a 383 for a fullsize truck everytime.

     
  12. k20

    k20 3/4 ton status

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    Ill concur with everything on here, I have 049 heads, put in some 2.19/1.88 valves, and did a little porting, mainly just gaskey matching.

    And yes a 496 is .030 overbore and .25" stroke.....:D
     
  13. tiger9297

    tiger9297 1/2 ton status

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    I guess I'm a little confused. I dig a little digging this afternoon and this site http://www.mortec.com/borstrok.htm shows the 454 and 496 to have the same bore but different stroke lengths. That is, if I'm reading this right.​
     
  14. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    A 496 is a 454 bored .060" with a 4.25" stroke crank.

    The formula for figuring out engine displacement is:

    Bore x Bore x Stroke x .7854 x number of cylinders.
     
  15. DEMON44

    DEMON44 Low-Tech Redneck

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    or V8 specific is
    bore x bore x stroke x 6.2832


    and the 496 listed on Mortec there is the late '90s Vortec 8100 engine. Yes works out to 496cid, but is not the same engine as stroking a carbed 454 to 496.
     
  16. k20

    k20 3/4 ton status

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    That is correct.
     
  17. tiger9297

    tiger9297 1/2 ton status

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    so..do you have to machine the 454 block to have enough clearance for the 4.25" stroke crank?

    Will the accessories- a/c compressor, alternator, water pump, p/s pump off of my 350 work w/ a BBC if I get the BBC brackets?
     
  18. k20

    k20 3/4 ton status

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    Some of em you will have to barely grind, some you wont have to at all, and some you will have to grind a fair bit. Mine didnt need any.

    Water pump wont work, p/s pump may or may not, depending on the brackets you get and the style of pump you have now. Same with the A/C compressor. The alternator will work.

    Also keep in mind you will need either a 4 core, or an aluminum radiator to keep up with the big block.
     
  19. SkysTheLimit

    SkysTheLimit 1/2 ton status

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    Yes, you will have to chamfer the edges so the piston rods will clear the bottom of the cylinder.
     

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