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BBC 454 build questions

Discussion in '1973-1991 K5 | Suburban | Truck' started by KeyBlazer, Dec 21, 2008.

  1. KeyBlazer

    KeyBlazer 1/2 ton status

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    Have a 454 sitting in my storage from a TBI 1990 Suburban.

    Not sure where it will end up, maybe in my 73 Blazer.
    Wanted some input/ideas on a suitable build..
    Have not full stripped it yet, but the crank was a little scored.
    Money is an issue at the moment but as and when I have funds I want a plan.
    So crank needs a grind, or maybe a .250 stroker but that means rods too and up goes the cost.
    I am sure the block needs boring.
    I have a set of +60 forged pistons that have raised domes... will post pics when I dig them out.
    Heads are peanut ports.
    Should I keep the TBI setup that I have and mod it?
    What is a reasonable power output to aim for?

    Give me ideas?
     
  2. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    Let me say that you can build some serious power with a 454 base. You really first need to make a choice if you're going with a carb or FI. I would ditch the peanut port heads and find some"781" heads and have them fitted with the 2.19"/1.88" valves and blend the bowls. Forget about the forged domed pistons you have, those will give too much compression and definately not wanted or needed for a truck engine. You should be looking to keep the CR close to 9:1-9.5:1 to keep it pump gas friendly without pinging issues. You can ask Burt4x4, Dremu, Greg72, bp71k5 how they like the engines i've built for them. Brian (bp71k5 is a 350 but all others are BBC's).
     
  3. KeyBlazer

    KeyBlazer 1/2 ton status

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    Cool!
    Can you give me some idea as to numbers(HP/TQ) or improvements compared to stock?

    What was the specs of the builds you did?

    I am stuck between FI and Carb... I would love th go the injected route with the edelbrock or an aftermarket setup, but thats $$$, so I am stuck with the TBI that I have, with mods or swapping to a carb.
     
  4. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    I can't remember the specs on each of these engines and i thought i had saved them but i can't find them right now. I can tell you though that i did a mild build on Dremu's 454 and it was making something like 580 ft/tq. PM Aaron (Dremu) i'm sure he'll remember the numbers or even have them saved.
     
  5. USSkoval

    USSkoval Dunno?

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    What were the 781 heads generally used on?
     
  6. KeyBlazer

    KeyBlazer 1/2 ton status

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  7. kevin400ex

    kevin400ex 1/2 ton status

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    depends on what your using the engine for. if your towing heavy loads the peanut port heads work fine. just grind the crank and put some forged flatops in it and rebuild the heads. an rv cam with .500 lift 214* /222* in/ex duration at .050 with a 112 center and youll have a torque monster. the cam specs listed are from an engle rv101/104hyd cam. i built this combo for a 30ft class a motorhome and used the stock iron intake with a quadrajet and thorley headers. coach weighed approx 20k lbs with my enclosed trailer with my dirt toys in it. i pulled the whitwater grade on the 10 in palm desert in the hammer lane no problem.

    all depends on what your intended use is as to which direction to go.
     
  8. KeyBlazer

    KeyBlazer 1/2 ton status

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    Sounds good!
    Is there anything that you can do to the peanut port heads to improve things?
     
  9. kevin400ex

    kevin400ex 1/2 ton status

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    a good three angle valve job is about it. if you doing stuff like mud bogs or sand where you need higher rpms then i would go with the bigger oval port heads, but for low rpm torque you dont need em.
     
  10. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    The "781" heads with the 2.19/1.88 valves will make tons of low end torque and still pull good up into the higher RPM range. Peanut port heads are only good for very low end torque and there are really no aftermarket intakes that match the ports of those heads.
     
  11. KeyBlazer

    KeyBlazer 1/2 ton status

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    Found a set of BBC heads... casting #3975950
    Mortec page says..
    3975950....68-70...oval...OPEN...396, 402 Truck, 366T, 427T

    Worth considering?
     
  12. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    You need to find the "781" casting heads (last three digits of the casting number). Those heads flow very well and even better with the larger valves installed.
     
  13. sweetk30

    sweetk30 professional hooker Premium Member

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    scott to bad you are there and i am here. i have 3 bbc that need a good buildup. i would love for you to build at least 1 of them . :doah:
     
  14. KeyBlazer

    KeyBlazer 1/2 ton status

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    Did some research...
    Looked in a old book I have..
    Hotrod Mag... Horsepower handbook BBC. p39
    An article about a junkyard BBC buildup.
    Core of motor was good, added a cam and Holley carb and got 376hp @4800rpm and 456lbft torque at 3900rpm.
    Those numbers look good to me, and they used the peanut port heads in the early stages.

    Onto costs... anyone had a block bored and or crank reground in SoCal recently?
    Costs?

    Also have these headers sitting in my storage that I was told will fit if I drop the BBC in my Blazer..
    [​IMG]

    DSC00153.JPG
     
  15. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    I'm making bigger numbers with a 350 and also at alot lower RPM range.
     
  16. USSkoval

    USSkoval Dunno?

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    Specs please:D
     
  17. KeyBlazer

    KeyBlazer 1/2 ton status

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    What should I expect to pay for the 781 heads?
     
  18. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    I wouldn't pay more than about $100.00 for a bare non cracked set.
     
  19. KeyBlazer

    KeyBlazer 1/2 ton status

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    I found my heads finally!
    336781 casting numbers that were oddly on a junkyard truck...
    The block was Chevy Orange but the heads were painted blue, so a swap in..
    Looks like I got there after the birds had pecked the rest clean, but left the heads... Intake and carb were gone as was the headers judging by the 3 bolt flange exhaust ...
    Will post pics later..
     
  20. 80' 427

    80' 427 1/2 ton status Premium Member

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    049s are just as good as 781 and they do make a aftermarket peanut port intake, its a weiand street warrior.
     

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