350 is out! 454 going in!!! Rear main seal question

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Blazer79, Nov 4, 2001.

  1. Blazer79

    Blazer79 1/2 ton status

    Feb 17, 2000
    Likes Received:
    Guatemala, Central America
    Hey guys!!

    I'm so happy. I finally removed the 350 last night. I'll be putting the 454 tomorrow. I'll post a few pics soon. It's so beautiful and shiny.

    Well, it's not rebuilt, just repainted and replaced all the gaskets and seals. Now for the final seal I have one question:
    Do I really need to remove the rear main cap to change the 2-piece seal? Or can it be pushed in there somehow?

    I'm asking this because I don't have a torque wrench right now, and being that tomorrow is sunday, my only choices would be to wait another week (I can only work on the Blazer on weekends now) or install it without one.

    Any ideas greatly appreciated.

    <font color=purple>//////
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    Soon a 454 K5!!</font color=black>
  2. motorheadnelson

    motorheadnelson Registered Member

    Aug 12, 2001
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    Fort Mohave AZ
    Yep, you have to remove the rear cap...and that is still a marginal way to do it. You may be able to roll it out, taping on it with a small drift, being careful not to nick the sealing surface, or using what they call a 'sneaky pete'..I think you can still get them. If you nick the surface, use some wet/dry 600 grit and polish it out, using a light oil...WD 40 even works. You may have to pop all of the main caps to do it right. When you re-install the seal, have the seal parting line .250" or so away from the mating surface, and put a dab of sealer on the ends...that will help prevent leaks. I'm building a 468" rat right now..forged pistons, forged crank, aftermarket everything, big valves, head work...lots of cool(expensive) stuff. Good Luck with the swap...I've done a previous BB swap...The only way to go...Rats Rule!!!

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