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'77 heads: Ok on unleaded?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Steve_87K5, Jan 15, 2001.

  1. Steve_87K5

    Steve_87K5 1/2 ton status

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    \'77 heads: Ok on unleaded?

    Am taking some '77 heads in for a valve job. Are these OK as-is for unleaded fuel, or should I have hard seats installed?
    Thanks.

    SteveB
     
  2. ken

    ken 1/2 ton status

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    Re: \'77 heads: Ok on unleaded?

    Those '77 heads (and any head made after 1975) should have the induction hardened seats which means you WILL NOT need hardened seats installed. I kinda don't like when a head is machined for seats, as the seats can come out and ruin your engine if you overheat it. I haven't had any problem with the induction hardened seats. The later model heads are even better, as they have the super duty exhaust valves too. Good luck.

    ken
     
  3. nyyef

    nyyef 1/2 ton status

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    Re: \'77 heads: Ok on unleaded?

    yeah theyll be alright. just for info.......the reason you should have hardened seats with unleaded is because in the old days lead in the fuel was kind of a lubricant. it also softened the impact of the valve closing. that way it didnt matter as much to have the seat a harder metal.

    Knife.
    knife.coloradok5.com
    <P ID="edit"><FONT SIZE=-1>Edited by nyyef on 01/15/01 10:55 AM (server time).</FONT></P>
     
  4. Steve_87K5

    Steve_87K5 1/2 ton status

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    Re: \'77 heads: Ok on unleaded?

    OK. Off they go to the machine shop. Was quoted $80 plus parts, and more if guides
    are needed. Thanks for the help!

    SteveB
     

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