273 Carb upgrade

Discussion in 'Fuel and Air Systems' started by Michael Brisebois, Jun 7, 2018.

  1. Michael Brisebois

    Michael Brisebois FABO Gold Member FABO Gold Member

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    I Have a 66 Barracuda with the "ol reliable" 273 2bbl. I'd like to go to a 4bbl and NOT really do anything else to the engine.

    Not looking to race, or anything like that...just a little more pedal. Anyone care to share an opinion?
     
  2. grimreaper

    grimreaper Cross Member

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    What intake manifold do you plan to use?
     
  3. toolmanmike

    toolmanmike FABO Staff Staff Member FABO Gold Member

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    Stock manifold and a 500- 600 Edelbrock works well. A Edelbrock LD4B manifold works well also.
     
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    • Michael Brisebois

      Michael Brisebois FABO Gold Member FABO Gold Member

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      Looking for a recommendation on that as well. I don't want to get into a cam, or head change
       
    • grimreaper

      grimreaper Cross Member

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      If you can find a fctory 273 4bbl manifold they work OK. As Toolmanmike said the Ld4B is a good choice too.
       
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      • rumblefish360

        rumblefish360 so close yet so far away

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        Just be careful of that early intake bolt angle. Being it is a 2 year run thing, aluminum intakes could be a pain to find. IDK

        ALSO! A 500 cfm Carter/Edelbrock would be very good on top. I myself would use the new AVS II 500 cfm unit.
         
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        • Michael Brisebois

          Michael Brisebois FABO Gold Member FABO Gold Member

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          Are you saying that a 1966 273 is different a later year 273/318/340/360?
           
        • toolmanmike

          toolmanmike FABO Staff Staff Member FABO Gold Member

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          64 and 65 are smaller bolts at a different angle. 66 and newer are the same.
           
        • rumblefish360

          rumblefish360 so close yet so far away

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          Sorry, no. My bad if I misread.
          The first two years are different. ‘64 & ‘65.

          The attaching bolt hardware is smaller in diameter.
          It also is drilled at a different angle.

          There! I said it twice.

          For the owners of the first two years of the 273, Believe it or not, disregard at your own risk. I’ll just say “I told you so.”
           
        • rumblefish360

          rumblefish360 so close yet so far away

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          And now reading back, I did misread.

          Sorry, my bad!
           
        • 318willrun

          318willrun Stomper 4x4... we kept energizer in business

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          Weiand action plus would work well also, and are reasonably priced new or 2nd hand.
           
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          • JBurch

            JBurch Well-Known Member

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            In the realm of " a little more pedal and not looking to race " you have actually a lot of choices: you have 66-67 factory cast iron 4 bbl, LD4B Edelbrock, Edelbrock Performer, Holley Street Dominator, even the despised Edelbrock SP2P; they all amount to "more" intake than the 2 bbl on the engine now. The factory cast iron intake is kinda rare, most popular with the resto crowd which can drive it's price, the LD4B is a Holy Grail intake and sellers ask money for them, the Performer is common, people step over them looking for an LD4B which makes them; the Performer; affordable, the Holley Street Dominator is an aluminum up-graded version of the factory cast iron, would be more suitable with more up-grades to your engine, the SP2P is a wild card here, designed in the early days of smog control, ment to be a low rpm boost in torque and fuel economy, some people are almost willing to pay people to take them off their hands; I will probably be burned in effigy for mentioning it.

            Carburetor choices, something in the range of 450 to 600 CFM

            You didn't say if standard or auto trans, if auto you will need kick down linkage

            Good luck!!
             
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            • toolmanmike

              toolmanmike FABO Staff Staff Member FABO Gold Member

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              There you have it!
               
            • Michael Brisebois

              Michael Brisebois FABO Gold Member FABO Gold Member

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              It's a 4 speed,
              I was leaning towards a 500cfm. Too much cfm in the past left me with a bog from the start off. I had a 69 340 many years ago and put on a variety of carbs on it, but kept coming back to the Carter 600 or 650 ( not sure now which it was)
               
            • Dartsun

              Dartsun FABO Gold Member FABO Gold Member

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              I’d recommend a 500cfm. I had a 600 edelbrock on my 65 273 2 barrel engine and was To much, cast iron intake. Dustin
               
            • dart4forte

              dart4forte FABO Gold Member FABO Gold Member

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              LD4B Edelbrock, Carter Competition 9636, 625 CFM, Electronic ignition. That will put some scoot into that fish. Later mods, 920 heads, you can install a .028 headgasket and get the CR up to 9 to 1, Isky style E4 camshaft, Comp Cams has a grind. Of course, the 273 needs some gears to get into the powerband quickly. Good start are some 3.23s


              This was one of my 273 projects from years ago

              273.jpg
               
              Last edited: Jun 8, 2018
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              • rumblefish360

                rumblefish360 so close yet so far away

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                Edit to the otherwise great description above would be;

                The Holley Street Dominator is a very low single plane intake much like the early 273’s.
                The Edel. Performer is very much like the factory cast iron intake. As such, it will perform just as well.

                The sp2p is a intake designed for mileage and torque increases. Not smog.
                 
              • toolmanmike

                toolmanmike FABO Staff Staff Member FABO Gold Member

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                I like the way you think.

                273 Build
                 
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                • dart4forte

                  dart4forte FABO Gold Member FABO Gold Member

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                  I wouldn't even consider a SP2P
                   
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                  • rumblefish360

                    rumblefish360 so close yet so far away

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                    Not unless I’m looking to do better than 25mpg’s!
                     
                  • JBurch

                    JBurch Well-Known Member

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                    I threw that out there even though people hate it based mostly on the fact that the OP stated he wanted "a little more pedal" and wasn't looking to dive any further into his engine other than carb and intake swap. Stock 2 bbl 273 is gonna be all done by about 4500 rpm, about the same place an SP2P is gonna lay down, seemed to me that, that was a good balance, it can be had cheep, it's just the nitch it was designed for.

                    The OP can do what ever he wishes to do, what ever his wallet will let him......it is/was just an idea along the lines of what the OP asked for....
                     
                  • dart4forte

                    dart4forte FABO Gold Member FABO Gold Member

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                    Point taken....
                     
                  • Slantsix64

                    Slantsix64 Well-Known Member

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                    I got great mileage with a 500 cfm eddy lb4d on a 273 . Great intake for a 273 or a 318
                     
                  • toolmanmike

                    toolmanmike FABO Staff Staff Member FABO Gold Member

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                    I have a stock cast 273 on mine with a 600 Edelbrock. I got 18 mpg on a 4 hour trip last weekend. I would like to put on a SP2P or a LD4B for a drivability and mileage test.