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Hot Rods Will my Hemi with cast pistons Handel a 671 blower

Discussion in 'The Hokey Ass Message Board' started by Jesse Duke, May 2, 2019.

  1. Jesse Duke
    Joined: Dec 16, 2018
    Posts: 6

    Jesse Duke

    loudbang and Deuces like this.
  2. sunbeam
    Joined: Oct 22, 2010
    Posts: 3,911


    The 9 to 1 is a little iffy with out big boost and staying out of detonation I would say yes. With your set up you are not going to see high rpm. That is the piston killer. I will get flack for that last statement.
    Last edited: May 2, 2019
    porknbeaner, loudbang and Jesse Duke like this.
  3. corncobcoupe
    Joined: May 26, 2001
    Posts: 4,475

    Staff Member

    9:00 to 1 compression ratio if I'm reading that right - that's on the edge.
    Is this a street driver only of strip ?
    Street - for a while as long as you are not really hammering/ revving it all the time....
    Strip - probably not for long.....

    Those blowers make a lot of power and can really blow stuff up - especially cast anything.
    Forged Pistons would be a lot better.

    My opinion
    Deuces, mgtstumpy and Jesse Duke like this.
  4. Jesse Duke
    Joined: Dec 16, 2018
    Posts: 6

    Jesse Duke

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  5. Jesse Duke
    Joined: Dec 16, 2018
    Posts: 6

    Jesse Duke

  6. This must be an afterthought?
    If you keep the max boost low is should be ok.

    But by doing that you’ll be making blower noises and dragging the parasitic loss just from driving the blower.

    Get forged pistons
    mgtstumpy likes this.
  7. lippy
    Joined: Sep 27, 2006
    Posts: 3,919

    from Ks

    Why would anyone take the chance on destroying an engine for the price of a set of pistons? Lippy
  8. squirrel
    Joined: Sep 23, 2004
    Posts: 41,982


    put a bigger cam in it, and you should be ok, as long as you don't get too wild with boost.
    Montana1 and mgtstumpy like this.
  9. I suppose why he asked the question.
    Ive got a hair up my ass to put a 671 on a bone stock SBC 307 :D with stock flat top pistons and the shitty stock heads. Those 307 boat anchors are almost free and not 10gs though.

    Sounds sweet don’t it?
  10. dreracecar
    Joined: Aug 27, 2009
    Posts: 2,689

    from so-cal

    Would not care about to much about the pistons as much as the boost, general rule is that you should o-ring the cyl's with anything over 9# of boost. and in reality using a non stripped blower (and a little loose for street) @ 3# will set you way back in the seat.
    saltracer219 likes this.
  11. Jack E/NJ
    Joined: Mar 5, 2011
    Posts: 530

    Jack E/NJ
    from NJ

    As is from Joe's Hemorrhoid shop will also set you way back in the seat plenty enough. Jack E/NJ
  12. Boryca
    Joined: Jul 18, 2011
    Posts: 541

    from Detroit

    I don't put cast pistons in anything I want to last very long anymore... Forged are always worth the money, in my opinion; especially if there's a power-adder or high compression involved.
    Montana1 and mgtstumpy like this.
  13. Jesse Duke
    Joined: Dec 16, 2018
    Posts: 6

    Jesse Duke

    I was going to buy the engine .. it it was a good price we worked out a deal I did some research and wanted to reach out for some other opinions

    Sent from my iPhone using The H.A.M.B. mobile app
  14. 41rodderz
    Joined: Sep 27, 2010
    Posts: 2,105

    from Oregon

    There you go. Smart to ask ?'s before you buy.
    mgtstumpy likes this.
  15. mgtstumpy
    Joined: Jul 20, 2006
    Posts: 7,219


    Would you double key way the crankshaft and harmonic balancer?
    Last edited: May 3, 2019
    Joined: Jul 20, 2006
    Posts: 1,521


    I wouldn't put cast pistons in anything anymore especially in blown applications. I had an experience with the engine in my convertible that makes me a believer in forged pistons. When I built the engine the only kit could buy had forged pistons, the engine always detonated and got worse the longer the engine was ran. Short story I had an engine knock when I got home from the lead sleds in Salina 3 years ago. Engine siezed a piston on the wrist pin. A cast piston would have been destroyed. A new piston , and rings ran a hone in the cylinder, engine is good as new. I did get the cause of the detonation fixed as well
  17. 73RR
    Joined: Jan 29, 2007
    Posts: 6,179


    In addition to the high 9:1 on a cast piston you also need to be cautious about the skinny connecting rods, and head gaskets. Lots-o-places for things to go wrong.

  18. porknbeaner
    Joined: Sep 12, 2003
    Posts: 40,902


    No you won't. As long as the boost is not silly high (I have an opinion on low boost but I'll keep it to my self) and you don't rev it 'til it comes a apart you should be fine.

    @sunbeam back in the '90s I had a friend at MOPAR Performance that said stuff that you could take to the bank and nearly everyone on this board would scoff at. I put some of the things he said to the test.
    He's retired now he was a grey beard back then and he knew his chit.
    Montana1 likes this.

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