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2 barrel vs. 4 barrel carburetor

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  • #16
    Carter WCFB. . Any downside to these carbs?
    It was the first and maybe the best 4-bbl carb ever built for smaller V8s.

    jack vines
    PackardV8

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    • #17
      I have never had vapor lock issues with a Carter WCFB in 70 and 80 degree Southern Calif. Weather.

      The early pre 1962 WCFB's did have a hard Right turn flooding minor issue, before they installed the Brass Float baffle between the Needle and Seat and the float.

      Maybe 90 to 105 degrees would require a better radiator, Fan Shroud, high output Fan, cool fuel return line, Carb. spacer etc.
      Last edited by StudeRich; 05-06-2013, 05:04 PM.
      StudeRich
      Second Generation Stude Driver,
      Proud '54 Starliner Owner
      SDC Member Since 1967

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      • #18
        Thanks, Jack, Rich and Mike. I feel better about going ahead with the swap. Car sounds nice with the dual exhaust. Should be a little quicker with the 4bbl. Better upgrade the brakes at the same time
        Dave Warren (Perry Mason by day, Perry Como by night)

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        • #19
          After the dual exhausts and 4-bbl carburetor, while changing manifolds, consider blocking off the exhaust heat riser passage with a stainless shim between the head and intake. If you only drive your Stude in mild weather, it will be an improvement.

          The next item of business is a complete ignition system upgrade. If you've already done this, please excuse.

          1. Have the distributor rebuilt and the vacuum and centrifugal advance curves verified on a machine.
          2. New points, condensor, rotor, cap, wires and plugs.
          3. Strongly advise a Pertronix conversion. I ran points for fifty years, but with the Stude V8 distributors living in the back of that long, dark tunnel, today, it's electronic.

          After the ignition is new, a valve adjust and you're ready for the PSMCDR.

          jack vines
          PackardV8

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          • #20
            Thanks, Jack. As far as the heat riser, the PSMCDR rules state "the choke assembly must be in place and functional". Would blocking off the heat riser affect the choke operation? I'll have the distributor checked out when I install the Pertronix. I have the unit and coil still in the box. I had the garage next door try to install a 6V Pertronix a couple of years ago and they said they couldn't get a signal from the Pertronix sensor. This time I'll have a couple of phone numbers for them to call if that situation pops up again. Cap, wires and plugs, for sure.
            Dave Warren (Perry Mason by day, Perry Como by night)

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            • #21
              The automatic choke won't work properly if you block off the heat riser passage. It relies on heat from a tube dipping into this passage to warm up the bimetal spring inside the choke to release it. If you block the heat riser, use an electric choke off a current-model AFB. (if that is within rules for the race venue).
              Gord Richmond, within Weasel range of the Alberta Badlands

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              • #22
                Even an electric choke will not work properly if you close off the heat riser. The choke will open before the carb is warmed up, and the engine will sputter and stumble, as if the regular choke was not working. Only way around the problem is a manual choke. Plus, once the engine is good and warm, 20 miles or so down the road, the manifold will still get hot enough to cause the carb bowl to percolate itself dry, just as if the heat riser was still functional. That was my experience with the 56J before. At least it was easy to shut off, then open back up; a 1.5" freeze plug taps nice and snugly into the exhaust crossover holes in the intake manifold.

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                • #23
                  Therein lies the rub. No manual chokes allowed, either. An electric choke would have to operate on 6V to be true to a stock 55. The best that I can do is make it perform like the best it could have been in 55. I won't be competing to be the fastest car there, but to find out how fast a stock 55 Studebaker could run - in its day. The only advantages I might have are weight, design, and options available in 55. The Commander has no power options, no leather interior, very little insulation and soundproofing, all new motor mounts, springs, universal joints, well built motor and rebuilt DG200 with first gear start. It seems like a pretty quick little combo. Disadvantages: pilot has no experience
                  Dave Warren (Perry Mason by day, Perry Como by night)

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                  • #24
                    FWIW this is what Chevy said adding a 4 bbl carb and dual exhaust did to the full throttle performance of the 1955 "New Chevrolet V8."

                    From the SAE paper in 1955 transactions.
                    Attached Files

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                    • #25
                      IIRC, the R-series intake manifold gaskets have the heat crossover partially blocked off. That still allows the choke to function.

                      jack vines.
                      PackardV8

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                      • #26
                        Key word there is "partially". Eventually, I suppose, even with a fully blocked-off heat riser, the manifold would get hot enough for the automatic choke to open, but how much raw gas are you going to let wash down the cylinder walls until that happens?

                        I'd be inclined to use the R-series restrictor gasket, and then set the choke as loose as possible, while still having some function. Sure, the car would be hard to start cold, but would run fine, once warmed up.

                        Second-guessing the rules a bit, but I wonder if the "functional choke" rule isn't mostly about ensuring that no competitor remove the choke butterfly altogether, for a few CFM more airflow, or blocks the heat riser ports to the heads and circulates ice-water through the crossover passage?
                        Gord Richmond, within Weasel range of the Alberta Badlands

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                        • #27
                          Dan, those HP ratings are surprisingly similar to what was published for the Stude 259. "Bearcat" 2 bbl was rated at 162.5 HP and "Passmaster" 4 bbl was rated at 185 HP. The Chevy 260-283 is a small block and the Stude 259 is a wedge. Would love to watch the two run and see if the low sleek C/K had any advantage over a boxy 55 Chev.
                          Dave Warren (Perry Mason by day, Perry Como by night)

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                          • #28
                            A single HP number ( HP at the brochure ) has long been a popular talking point, as is torque more recently.

                            I think throttle response and breadth of powerband is not well characterized or portrayed by those numbers, and they are what I feel when driving around. A responsive frisky engine makes a frisky feeling car.

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                            • #29
                              Jack, now that R series gasket has possibilities ))) and I think Gord is right about sandbaggers who might try to bend some more rules, too. I'm trying to do it the honest way. Don't wanna beat the next guy in line, but I really want to see what the hottest stock Stude in '55 would do. I'll leave the 331 non TT set up as I don't think I'll be doing a burnout. I've come close to reading 100 MPH on the 4 lane without shaking her apart....and I have to drive it there, 400 miles. Getting back may be a problem (lol).
                              Dave Warren (Perry Mason by day, Perry Como by night)

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                              • #30
                                Originally posted by Dan Timberlake View Post
                                FWIW this is what Chevy said adding a 4 bbl carb and dual exhaust did to the full throttle performance of the 1955 "New Chevrolet V8."

                                From the SAE paper in 1955 transactions.
                                There is an interesting loss of Torque between 1600 and 2600 RPM. Everything else looks a bit better on the little 265 with Power Pack vs. 2 Barrel.

                                Looks like it needed a better curve in the Distributor advance.
                                StudeRich
                                Second Generation Stude Driver,
                                Proud '54 Starliner Owner
                                SDC Member Since 1967

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