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Big Block in a 72

Discussion in '1969-1972 K5 Blazer | Truck | Suburban' started by bryanrash, Feb 6, 2006.

  1. bryanrash

    bryanrash Registered Member

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    I know some of you lucky guys have put BB power in your blazers. What type of modifications were required to fit it in there? I just got a beat up 72 truck and was thinking about putting a 454 or 502 in it. Down the road sometime I plan to yank it all and put it in a 1st gen blazer. I assume the engine compartments are relatively similiar so I figured I would take my first crack at it with this truck. What major issues am I going to run into?
     
  2. rcamacho

    rcamacho 1/2 ton status

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    I'm running a 402 in my '87. Pretty much a straight swap presuming you have a bigger rad and all the accessories.
     
  3. vtblazer

    vtblazer 1/2 ton status GMOTM Winner

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    A big blocks fits in/came factory in the 2wd's, what's your new truck?
    First year to have a big block in a 4x4 was 73. (when everything changed)

    It's a tight fit back near the firewall, seen several different ways to work around it.:hack: The cross member clearance is another area to deal with.
    Motor mounts, oil pan, valve covers...all have possible variation's.

    Try the search, I'd bet there's lots of past threads on the subject having all the info you'll need.
     
  4. Burt4x4

    Burt4x4 3/4 ton status

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    Nope can't be done yer stuck with a SBC..hahahah J/K

    You can drop one in with minimul mods or you can go all out and make a ton of mods. So depends on what your after and how much time and money you have or don't have.

    One thing for sure there are variations on how the BBC will fit. What I mean is all the research and talking with other folks that have done this, with the early firstgen K5 engine bays there are differences even in the same year truck...different plants put then togeather I guess?
    Like Greg72 has a 396 and he had to notch his frame a tiny bit to get the Thorley heders to clear..were me in my 72 w/454 I did not cleard by about 1/8".
    The firewall on the drivers side will hit so some beat the hell out of the firewall and some make custom cuts & patch work.
    All in all SBC engine mounts & bell will bolt to a BBC so if you wanted you could pull the SBC and beat the firewall toss in the BBC, change to a bigger radator and go play (assuming you have a complete BBC).
    Have fun
     
  5. RGV72BLAZER

    RGV72BLAZER 1/2 ton status

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    some pre73 chevys did come equipped with the 402 BBC. firewall clearance will probably be the biggest issue. if you have enough lift, then oil pan clearance shouldn't be a problem. if not, then you're gonna have to look for a low profile pan. or maybe you can add a body lift (something i wouldn't do) if you don't want to bash the crap out of your firewall. but it can be done. i'd like to swap a 454 into my '72. good luck.
     
  6. vtblazer

    vtblazer 1/2 ton status GMOTM Winner

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    Only the 2wd's had the 402, 4x4's never got a big block until 73.

    Unfortunately...:rolleyes:
     
  7. RGV72BLAZER

    RGV72BLAZER 1/2 ton status

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    ...aaah ha, i see...i'm planning on just swapping in my sbc 350 in my '94 'yota, & then put the 4 mean squirrels out of the 'yota in my Blazer, no firewall clearance problems, no sagging springs, & great fuel economy :eek1: :yikes:
     
  8. Burt4x4

    Burt4x4 3/4 ton status

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    Well I have a 3" body lift and I did need to bash in the firewall a little bit. I would gues without the lift the bashing would be a bit more than what I had to do....haveing a dented firewall is worth the BBC...go-for-it:D
     
  9. bryanrash

    bryanrash Registered Member

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    72 4x4 Shortbed to Blazer

    This is a 72 4x4 1/2 ton shortbed truck. Are the modifications I make to this truck going to swap over to a blazer down the road when I get one? Will the lift and drivetrain match up? I realize the engine bay might have some minor differences, but what about the rest?

    Thanks for all the comments. I have been checking out all the picks of monster engines and hope I will be able to follow in your steps in the near future.
     
  10. jaros44

    jaros44 1/2 ton status

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    Bbc

    As if I wasn't envious enough, I have read about you BBC guys Wheeling in Vermont or Dyno testing your engines, enough is enough!!! Maybe someday, but I'm stuck with my mouse motor. Enjoy, I'll be here reading about all the good things you get to do. Maybe next it will be my turn. Ha Ha Later J.
     

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