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HEI clearance

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by skyblazer, Feb 26, 2001.

  1. skyblazer

    skyblazer 1/2 ton status

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    I thought I had read that an HEI distributor may cause firewall clearance problems on a 72 K5 with a 350. Can anyone fill me in? I have the body and engine out and can't take any measurements. I will be starting the body work soon and need to know if I should do any firewall mods to fit a new distributor, probably stock GM HEI or maybe MSD.
     
  2. pcorssmit

    pcorssmit 1/2 ton status

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    My little brother's got a GM HEI in his '70 (w/350), when he first put it in the distributor hit the firewall when driving/wheeling and caused problems. His solution was to pull the distributor (and the carb, I think) and give the firewall a few solid hits with the 3lb. hammer. Seemed to fix the prob.
    If you don't want to bash in the firewall, you may want to go with a Pertronix kit, it converts your stock distributor to electronic, they're around $70 (try Summit).

    Pete

    '83 K5, 350 TBI (ex 6.2), 700R4, NP208, Dana 60/14 bolt, 4.56s, Detroits, 3" lift, 15-39.5x15 TSLs
    '97 Dodge 2500 4x4 CC LB Sport, Cummins 5 spd
     
  3. Blazer1970

    Blazer1970 1/2 ton status

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    I have an HEI on my '70 Blazer. It is very close to the firewall, but doesn't hit. I could see where it could hit if you really twisted it up, in particular if the body is in bad shape, or if you have a bad motor mount.

    Tim

    70 Blazer CST 4X4 350 SM465 NP205
    87 Burb 4X4 350
    01 GMC 2500HD 4X4 Duramax/Allison
     
  4. dyeager535

    dyeager535 1 ton status Premium Member

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    If you wanted to, you could always go to a late 80's setup, they went BACK to a divorced coil, so its got a smaller cap. Might fit better depending on where the clearance issues are.

    Dorian
    My K5 and Chev/Olds tech/links page: <A target="_blank" HREF=http://www.dorianyeager.com/index2.html>http://www.dorianyeager.com/index2.html</A>
     
  5. Shawn

    Shawn 1/2 ton status Premium Member Author

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    I was able to fit one in my old 70 Chevy 2wd with no problems. I think the only problem you would have is if you dropped your t-case. Take Petes advice and get a hammer or get a smaller MSD or Accel distributor. I don't think a newer GM distributor will work since there's no mech. or vacuum advance on those (computer controlled advance).


    Shawn
    87 K5
    few mods[​IMG]
    <A target="_blank" HREF=http://www.off-road.com/chevy>http://www.off-road.com/chevy</A>
     
  6. dyeager535

    dyeager535 1 ton status Premium Member

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    hmm. Yeah, never thought about that..theres no way to put the newer cap on the non CCC distributor? The housing were pretty similar, but from what I have seen, the actual shaft is different. It still had to have the pad that the weights attached to, since the rotor bolts to it. I should do some testing on that : ) Auto parts store will love me hehe


    Dorian
    My K5 and Chev/Olds tech/links page: <A target="_blank" HREF=http://www.dorianyeager.com/index2.html>http://www.dorianyeager.com/index2.html</A>
     
  7. Blazer1970

    Blazer1970 1/2 ton status

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    In the '67 - '72 model years, the motor sits farther back in 4WD trucks than in a 2WD. HEI will fit pretty easy on a 2WD, very tight in a 4WD.

    Tim

    70 Blazer CST 4X4 350 SM465 NP205
    87 Burb 4X4 350
    01 GMC 2500HD 4X4 Duramax/Allison
     

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