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Technical Pontiac Head Question

Discussion in 'Traditional Hot Rods' started by 31hotrodguy, Mar 17, 2020.

  1. 31hotrodguy
    Joined: Oct 29, 2013
    Posts: 2,256

    31hotrodguy
    Member

    Hmmm I think 670’s would put me right about in the same place as my current 797’s on the 389.


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  2. No help on the heads. But i had a 1968 pontiac 350 HO, which i believe had the ram air III heads and man, that thing moved!

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  3. Deuces
    Joined: Nov 3, 2009
    Posts: 19,172

    Deuces
    Member
    from Michigan

    Pictures????..... :)
     
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  4. Joe H
    Joined: Feb 10, 2008
    Posts: 964

    Joe H
    Member

    I haven't checked any of the aluminum heads, but I have heard the new " D " port heads run decent. The early aluminum heads along with the racing heads have big runners, the velocity through them is terrible till you get the RPM way up. The newest " D " port aluminum have small runners. Here is a link about the new KRE heads,
    http://www.tinindianperformance.com/kauffman-aluminum-d-port-pontiac-cylinder-head/
    With any aluminum head, you can run at least 1 point higher compression on the same fuel as you would iron heads due to the rapid heat dissipation.
     
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  5. saltflats
    Joined: Aug 14, 2007
    Posts: 10,378

    saltflats
    Member
    from Missouri

    20200325_101306.jpg
    20200325_101405.jpg
    20200325_101440.jpg
    :cool:
     
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  6. Deuces
    Joined: Nov 3, 2009
    Posts: 19,172

    Deuces
    Member
    from Michigan

    Cool! Thanks for posting those.....:cool::)
     
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  7. derbydad276
    Joined: May 29, 2011
    Posts: 1,321

    derbydad276
    Member

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  8. Elcohaulic
    Joined: Dec 27, 2017
    Posts: 1,418

    Elcohaulic
    Member

    Those 1967 670 heads are the ultimate... Put on a set of those heads with a fresh 068 cam and have fun..
     
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  9. 31hotrodguy
    Joined: Oct 29, 2013
    Posts: 2,256

    31hotrodguy
    Member

    Still learning about Pontiac as I go. Especially when it comes to the heads. My Chevy brain is going in circles trying to figure out which heads are better than others.
    So are the 670 heads basically the same as the 16 heads in 68? A lot of the heads have the same size valves but do they flow the same?
    And how do they compare with say the later large chamber heads like the 7K3 or the 6x?
    This is keeping me up at night? Lol


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  10. Deuces
    Joined: Nov 3, 2009
    Posts: 19,172

    Deuces
    Member
    from Michigan

    Yeah and how do those heads compare to the 405 h.p. + 421 heads????..... :)
    Inquiring minds want to know.... :confused:;)
     
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  11. 31hotrodguy
    Joined: Oct 29, 2013
    Posts: 2,256

    31hotrodguy
    Member

    I guess I can always buy “the” Pontiac book online for $300 plus dollars!


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  12. Johnboy34
    Joined: Jul 12, 2011
    Posts: 1,333

    Johnboy34
    Member
    from Seattle,Wa

    Have you stuck a bore scope in a spark plug hole to see what pistons it has?

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  13. 31hotrodguy
    Joined: Oct 29, 2013
    Posts: 2,256

    31hotrodguy
    Member

    Not yet. I currently don’t have a note scope. I need to order one.


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  14. 31hotrodguy
    Joined: Oct 29, 2013
    Posts: 2,256

    31hotrodguy
    Member

    I meant bore scope but for some auto correct didn’t like that. They are definitely cheaper than they were a few years back.


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  15. s55mercury66
    Joined: Jul 6, 2009
    Posts: 3,980

    s55mercury66
    Member
    from SW Wyoming

    Since you aren't (or are you?) going class racing, you probably won't notice much difference in any of the large valve heads. I would be more concerned about getting the compression ratio where you want it, than picking the absolute "best" head. Bear in mind that rebuild costs may get you close enough to aftermarket new to make that option the best one.
    However, that really doesn't answer the question, hopefully someone will come along that will be able to.
     
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  16. Joe H
    Joined: Feb 10, 2008
    Posts: 964

    Joe H
    Member

    Even racing, stock heads will all perform about the same. In '65, the good heads were #093, used on both 389 and 421's with 68 cc chambers. 389 was rated at 10-1, 421 was rated at 10.5-1 compression, yet all the charts show 1/2 point less actual compression,dad and I have found this to be true on most of the heads we have checked over the years.
    This is my dad's book, https://www.amazon.com/How-Build-Performance-Pontiac-Design/dp/1884089674 , wish we had some more of them, I could make pretty good money selling at this price!
     
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  17. 31hotrodguy
    Joined: Oct 29, 2013
    Posts: 2,256

    31hotrodguy
    Member

    I’m not planning on class racing. I would like to run the car but just for fun. Plan now is to get it running with the stock63 389, then go bigger within the next year or two. Just a fun stock looking street car.
    I’m just trying to figure out the Pontiac heads in regards to is it worth it to try and find a certain head and pay the money or can I go with some of the other less coveted heads and still make good power.
    Scott


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  18. 31hotrodguy
    Joined: Oct 29, 2013
    Posts: 2,256

    31hotrodguy
    Member

    Awe yes, how many times did I walk by that book on the shelf at the book store only to think “I’ll buy it next time” only to see it now advertise for $300 plus!



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  19. s55mercury66
    Joined: Jul 6, 2009
    Posts: 3,980

    s55mercury66
    Member
    from SW Wyoming

    I would most certainly say yes, go with a set of big valve heads, and you should be most happy. The large chamber 6X heads you already have would probably work well on a 455, if you have a set of 16's, those might work well with the 389 combo, check the compression ratio, it might be close, but doable. Camshaft choice may be helpful if compression is too high, your manual trans will work in your favor there.
     
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  20. Starlinerdude
    Joined: Mar 6, 2008
    Posts: 130

    Starlinerdude
    Member
    from Washington

    There are few different early- mid 70's vintage heads that would work well with a 389,the ones that were original equipment on Pontiac 350's typically had a chamber size of 87-93 cc,some 400's had a chamber size of 96-99 cc these could all be brought down 87-90cc range without excessive milling,you may have to install larger valves a lot of these heads had the smaller valves.If you do plan on installing larger valves on a set of heads make sure you do that prior to doing any cc measurement because larger valve heads can change that.
     
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  21. saltflats
    Joined: Aug 14, 2007
    Posts: 10,378

    saltflats
    Member
    from Missouri

    And change them to 45 degree valve and seat angle.
     
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