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Big block install?'s

Discussion in 'The Garage' started by OLD DAWG, Oct 8, 2002.

  1. OLD DAWG

    OLD DAWG 1/2 ton status

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    Big block install?\'s

    I need some info on a 454 install into my 72 K5. First what is the best and or easiest way to do this transplant (I have an auto,PS,PB,and no Ac? Second ? is I need to find the combustion chamber cc of the heads casting #886781 so I can order the right compression ratio pistons. Thanks Doug/AKA OLD DAWG /forums/images/graemlins/confused.gif
     
  2. nvrenuf

    nvrenuf NONE shall pass! Premium Member

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    Re: Big block install?\'s

    Different books have printed different chamber sizes for the #781 heads ranging from 110cc to 119cc. The majority of books will say 116cc to 119cc. Although I have never had a set cc'd I think they are actually 119cc.
     
  3. Sandman

    Sandman 3/4 ton status Author

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    Re: Big block install?\'s

    Well, I dont show an 886781 but I do show a 336781

    336781.....73-85...oval...OPEN...454, 118cc chamber, 256/114cc ports

    The engine should basically be a bolt in. Same motor mounts. You will need the flywheel as it is externally balanced and is for the 454. You can rob one from a SB 400, I have and it works fine. The accesory brackets are all different also, so you'll need those. Good luck with the swap.
     
  4. TopOff

    TopOff 1/2 ton status

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    Re: Big block install?\'s

    I just put a 396 into my friends 72 K5 with A/C.

    It slipped in, tight but it went in.
    We had problems stabbing the tranny (SM465). Got it eventually though.

    Also the valve cover ended-up getting chewed up by the upper passenger bolt on the throttle pedal as it sticks through into the engine compartment THAT'S HOW TIGHT it is!

    Headers were LOADS of fun too!! Mucho custom bending on the headers, and a little frame cutting on the passenger side.

    Don't get long headers - these make a tight fit on the front driveshaft.

    Have FUN!
     
  5. OLD DAWG

    OLD DAWG 1/2 ton status

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    Re: Big block install?\'s

    Thanks' for the info guys, I got lucky and got a running, but in need of a rebuild, complete with all brackets, starter, alt., water pump, flywheel, etc. etc. 454 from a 76 SUB. for $325. Time to let the fun begin /forums/images/graemlins/grin.gif
     
  6. thatK30guy

    thatK30guy 1 ton status Premium Member

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    Re: Big block install?\'s

    Here's a tip to use when installing aftermarket headers into the pre-'73 trucks:

    Remove the engine crossmember on the '67 to '72 (whatever year yours is) and install a newer crossmember from any truck '73 to '87 (up to '91 Blazer and Sub).
    These newer crossmembers will require some drilling for new holes, but will fit right in easily.
    These newer crossmembers will allow the necessary clearance to fit any aftermarket header into these older trucks, especially to fit the BBC. /forums/images/graemlins/wink.gif /forums/images/graemlins/thumb.gif
     
  7. TopOff

    TopOff 1/2 ton status

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    Re: Big block install?\'s

    Those cross-members will require the later engine mounts too... right?

    My friend is a stickler for the '72 and earlier. He doesn't like the 2nd Gens at all.... /forums/images/graemlins/ignore.gif
    I am sure he would consider it sacrilige to use a 2nd gen cross member. /forums/images/graemlins/rolleyes.gif

    But why would you need to do this?!!?!

    The 1st Gens had Big Blocks (although not the 4x4s).
    Are the 2 wheel drive and the 4 wheel drive cross-members that different???

    Thanks for the info thatK30guy
     
  8. thatK30guy

    thatK30guy 1 ton status Premium Member

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    Re: Big block install?\'s

    True, the 4x2's had the BBC's and not the 4x4's.

    Yes, the crossmembers are different between the two.

    The whole idea to swap in the later crossmember was to allow the use of aftermarket headers for the BBC. If you have not noticed, there are not, if any, very many headers available for the 1st Gen 4x4's using a BBC. /forums/images/graemlins/wink.gif
     
  9. TopOff

    TopOff 1/2 ton status

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    Re: Big block install?\'s

    Could you run a 4x2 crossmember in the 4x4 1st gens?
     
  10. thatK30guy

    thatK30guy 1 ton status Premium Member

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    Re: Big block install?\'s

    LMAO! /forums/images/graemlins/laugh.gif

    I don't know as I've never heard or seen it done. I don't see why it wouldn't work. Just basically swapping one crossmember for the other.
     

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