You've heard it before ?

Slant 6 Engines

  1. Matt Gentile

    Matt Gentile Active Member

    Messages:
    36
    Likes Received:
    25
    Joined:
    Jun 2, 2018
    Location:
    MA
    Local Time:
    1:02 PM
    First slant six in my Mopar career...always 440's...now I want the challenge of the six that's in my newly acquired 68 Valiant . I have headers ( 2-3's ) , a Clifford intake ( with a single , dual and four barrel adaptors ) , will be doing an electronic distributor and full dual 2 1/4 exhaust...to start . So to start off , what carb ? Looking at a 390 cfm Holley 4 bbl or a 350ish cfm 2 barrel Holley ? Prefer not to dig into the engine , looking for reliability first , but if something looks do-able well....

    So anyways , I'm open to most anything as this route is all new , so what do you'ze guys think ?

    Thanks .
     
    • Like Like x 2
    • KosmicKuda

      KosmicKuda FABO Gold Member FABO Gold Member

      Messages:
      1,653
      Likes Received:
      479
      Joined:
      Jan 15, 2011
      Location:
      N Ohio
      Local Time:
      4:02 PM
      I think you should post this in the /6 section.

      What are your goals for this engine and car?
       
    • Bad Sport

      Bad Sport HALF A BUBBLE OFF Staff Member FABO Gold Member

      Messages:
      37,002
      Likes Received:
      17355
      Joined:
      Jun 12, 2010
      Location:
      The Wolverine
      Local Time:
      4:02 PM
      It is now. :D
       
    • Matt Gentile

      Matt Gentile Active Member

      Messages:
      36
      Likes Received:
      25
      Joined:
      Jun 2, 2018
      Location:
      MA
      Local Time:
      1:02 PM
      Sorry...
       
    • armyofchuckness

      armyofchuckness The Flying Valiant

      Messages:
      689
      Likes Received:
      107
      Joined:
      Aug 23, 2008
      Location:
      Gainesville, FL
      Local Time:
      4:02 PM
      If you aren't doing anything to the internals, the two barrel Holley is the way to go.

      If you're going for an electronic ignition, you should definitely do the HEI conversion.
       
    • RAT ROD AL

      RAT ROD AL I know just enough to be dangerous FABO Gold Member

      Messages:
      2,845
      Likes Received:
      3089
      Joined:
      Jan 18, 2013
      Location:
      St. James City. FL.
      Local Time:
      4:02 PM
      A few years back I built a /6 in a little rat rod , Put an Offy 4 barrel intake ,390 holley and performance cam in and it ran great.
       
    • 65 Dartman

      65 Dartman FABO Gold Member FABO Gold Member

      Messages:
      10,721
      Likes Received:
      2534
      Joined:
      Sep 24, 2006
      Location:
      Strasburg, VA
      Local Time:
      4:02 PM
      You really need to up the compression to take advantage of any external mods. I decked my block 90 thou and cut the head 10. Should up the CR to around 9.5 to 1. I haven’t decided whether to go 4 barrel or triple Weber’s
       
    • justme

      justme Well-Known Member

      Messages:
      318
      Likes Received:
      73
      Joined:
      Mar 12, 2007
      Location:
      long island new york
      Local Time:
      4:02 PM
      I use a 350 holley with pertronix and dual exhaust with Dutra manifolds, 833od. Lots of fun and i can cruz at 65, 75 very easily!!! Lots and lots of fun!!!
       
    • Matt Gentile

      Matt Gentile Active Member

      Messages:
      36
      Likes Received:
      25
      Joined:
      Jun 2, 2018
      Location:
      MA
      Local Time:
      1:02 PM
      On the 350 Holley...2 or 4 bbl ? And model...?
       
    • halfafish

      halfafish 66 Valiant, hot-rod in training FABO Gold Member

      Messages:
      964
      Likes Received:
      771
      Joined:
      Aug 14, 2016
      Location:
      SW Washington
      Local Time:
      1:02 PM
      First off, nice score on the 68 Valiant. I'm jealous, while keeping an eye out for the same car. I agree with all the above advice. Making a master plan is important, what are your goals for the car? With a slant, balancing complementary parts is a huge part of improving performance as opposed to throwing parts at the project. Doing the HEI ignition and recurving your distributor are a good start. Living in MA, unless you only drive this on only your hot summer days you will regret not having any intake manifold heat. Does your Clifford manifold have the water jacket? A far better route for a street driven car than headers are Dutra Duals. Yes, they are now more expensive since they were bought out by Aussie Speed, but they really work and are worth the coin. If you don't want to get into the internals, you are wasting your time and money with any 4-barrel carb. You need a bigger cam, more compression, and head work to get any benefit from a 4-barrel. The 2-barrel Holley is a better way to go (or a Carter BBD, or a Ford 2100). For exhaust, on any slant full duals are not necessary. If you want them because you like them, then fine. But it's extra weight that won't improve your performance a bit. A single exhaust properly set up will be better and cheaper.
       
    • justme

      justme Well-Known Member

      Messages:
      318
      Likes Received:
      73
      Joined:
      Mar 12, 2007
      Location:
      long island new york
      Local Time:
      4:02 PM
      2bbl
       
    • RAT ROD AL

      RAT ROD AL I know just enough to be dangerous FABO Gold Member

      Messages:
      2,845
      Likes Received:
      3089
      Joined:
      Jan 18, 2013
      Location:
      St. James City. FL.
      Local Time:
      4:02 PM
      I still have the two 2barrel 2100 carbs that fit your intake. CHEAP !
       
    • AJ/FormS

      AJ/FormS 68 B'cuda fb, Form S clone ... 367/A833/3.55s

      Messages:
      17,330
      Likes Received:
      5778
      Joined:
      Jan 19, 2014
      Location:
      South-Central Manitoba,Canada, 900ftelevation
      Local Time:
      3:02 PM
      3.40x4.125 stroke on the 225
       
    • Nige

      Nige Member

      Messages:
      13
      Likes Received:
      16
      Joined:
      Mar 9, 2015
      Location:
      Victoria, BC
      Local Time:
      1:02 PM
      shave your head :eek:
       
      • Agree Agree x 1
      • /sixchall

        /sixchall Well-Known Member

        Messages:
        183
        Likes Received:
        106
        Joined:
        Jan 19, 2017
        Location:
        Riverside ca.
        Local Time:
        1:02 PM
        For a little kick and efficiency I addressed my Six with (and this is a ‘77 model engine) a Mopar elect. Ign. With orange box and HO Accel coil. Then moved to an open element 14x3 K&N air filter, a Super Six intake and 2bbl Carter BBD, Hooker headers 3into1, real 2 1/4 aluminized dual exhaust w/ H pipe. 2 Glas Pak mufflers out to the back. A Nippondenso HO alum. starter for giggles. An 8 3/4 out back with a 3.23 gear set doesn’t hurt either, Auto. 904 all packaged up in a ‘70 Challenger. I think it sounds and runs great, nothing really over the top. Just damned efficient with 87 at the pump.
         
      • Slantsix64

        Slantsix64 Well-Known Member

        Messages:
        2,125
        Likes Received:
        776
        Joined:
        May 11, 2014
        Location:
        SGV
        Local Time:
        3:02 PM
        Mill the head, and choose a camshaft based on your rear ratio and compression ratio. Adding more gas and air to a stock slant camshaft is death.
         
        • Agree Agree x 1
        • famous bob

          famous bob mopar misfit FABO Gold Member

          Messages:
          14,921
          Likes Received:
          5233
          Joined:
          Aug 14, 2011
          Location:
          okla
          Local Time:
          3:02 PM
          6 cyl. w/ glass packs ? -----------------
           
        • AJ/FormS

          AJ/FormS 68 B'cuda fb, Form S clone ... 367/A833/3.55s

          Messages:
          17,330
          Likes Received:
          5778
          Joined:
          Jan 19, 2014
          Location:
          South-Central Manitoba,Canada, 900ftelevation
          Local Time:
          3:02 PM
          3.40 x 4.125, makes a swept of 613.72;That's
          ~9% more than a 273(562.2), and
          ~94% as much as a 318(652.27).
          that's a lot, eh?
          Huyp, that will make, making cylinder pressure, a little easier. And you only have to cut ONE head, and it doesn't mess up the valley seal,lol.
           
        • /sixchall

          /sixchall Well-Known Member

          Messages:
          183
          Likes Received:
          106
          Joined:
          Jan 19, 2017
          Location:
          Riverside ca.
          Local Time:
          1:02 PM
          not as bad as it sounds Bob! 2, 26” on each pipe with the H pipe connecting the two separate pipes together, at idle at the back it has a nice almost small block rumble.when I take off then you get the 6 cyl. sound. Thanks, Al
           
        • famous bob

          famous bob mopar misfit FABO Gold Member

          Messages:
          14,921
          Likes Received:
          5233
          Joined:
          Aug 14, 2011
          Location:
          okla
          Local Time:
          3:02 PM
          I just changed solid roller cams, mine makes more noise underneath now than it did w/ a hair bigger cam ???
           
        1. This site uses cookies to help personalize content, tailor your experience and to keep you logged in if you register.
          By continuing to use this site, you are consenting to our use of cookies.