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What carb are you running on a 2bbl V6?

Discussion in 'Modified Alpine' started by NorCal, Jan 29, 2021.

  1. NorCal

    NorCal Silver Level Sponsor

    I'm running a 32/34 with a 90 degree adapter and I'm starting to wonder if this is the cause of my car being such a dog. What carb are you running? Anyone running a 38/38 (corrected) ?
    Last edited: Jan 29, 2021
  2. RootesRacer

    RootesRacer Platinum Level Sponsor

    You can also fit a 38/38dgas on that same bolt pattern.
    There is also a 40DFAV available but they are hens teeth.
  3. NorCal

    NorCal Silver Level Sponsor

    I know the 38/38 has both butterflies of the carbs directly linked, where the 32/36 one side is progressive. The way the intake is I needed the 90 degree adapter to make sure all 6 cylinders got fuel. I am thinking with the 38/38, this wouldn't be needed. Is anyone running the 38/38?
  4. husky drvr

    husky drvr Platinum Level Sponsor


    I think what you are considering, eliminating the spacer, has been tried and wasn't directly workable. IIRC, the problem involves the linkage. The Weber DGS carbs all seem to have linkage arms that rotate below the base of the carb. Further, being buried between the valve covers leaves no room to connect the linkage for operation. It's possible your riser stand is two pieces, one being about an inch thick with one or two ports. I don't remember what my Dad's Capri was like forty years ago. If you have such a part and retain it, you might succeed with that conversion. If you aren't that lucky, you will need to plan to fabricate a spacer to lift the carb enough to enable linkage function.

    While linkage is under discussion, have you ever checked to see if your carb linkage will completely open the throttle butterflies by operating the foot pedal?

    In Cali, are you subject to smog testing, due to your v6? Are you using the stock Ford air cleaner, or the small rectangular Weber air cleaner?

    Was the Capri rear axle installed at the same time as the engine and trans? Do you know what ratio is in your rear axle? What size wheels and tires are installed on your Alpine?

    If you could post some pics of your carb, distributor, and I presume, your vacuum hose connections, someone might see something else to discuss.
  5. NorCal

    NorCal Silver Level Sponsor

    Is very one running a 4bbl intake / carb?
  6. NorCal

    NorCal Silver Level Sponsor

    Thank you for the reply. I could always retain the spacer if required.

    to answer your questions.
    - the carb is fully opened when the pedal is on the floor.
    - I have driven with the air cleaner removed with similar results.
    - it uses ‘73 Capri engine, trans, rear
    -185/55/15 on the tires.
    - good compression
    - new electronic disti
    - new plugs, wires, cap
    - timed and advances

    Motor starts first click, revs cleanly, but just has little get up and go. It could be my expectations.

  7. 260Alpine

    260Alpine Silver Level Sponsor

    Mike Armstrong has the Holley 2 barrel. You also have the stock cam and exhaust manifolds. I wonder if you could use the 2.8 heads, Ranger or Offy intake with DanR's headers and the Comp cam?
  8. RootesRacer

    RootesRacer Platinum Level Sponsor

    I am pretty sure the larger 2bbl intake on the 75 to 77 capri/mustang 2.8 will take a holley 2300 which is a higher CFM than the smaller holley/weber carbs. The stock motorcraft 2150 is also higher CFM but not as good or tunable as the Holley 2300, which IIRC is half a 4150 4bbl.
  9. 260Alpine

    260Alpine Silver Level Sponsor

    Actually, the 79 Capri was like the Mustang II. The earlier ones had the Euro heads and intake. Two exhaust ports on each head and different intake port alignment. You can swap from one to the other but the intake has to match the heads. The early Capri used the small journal cam like the Mustang II. May want to mill the later heads to gain compression.
    NorCal likes this.
  10. Mike Armstrong

    Mike Armstrong Bronze Level Sponsor

  11. todd reid

    todd reid Gold Level Sponsor

    My car is very similar to yours. I started with the engine, trans & 3.22 rear from a 74 Capri, then later upgraded to T9 5 speed. I am running the original Motorcraft carb with all the pollution stuff removed. 195/60 15 tires. I would say the acceleration is a notch better than a stock Alpine, but presumably nowhere near what some of the guys here with the full "Jose" treatment have achieved. I am not sure what your expectations are (my car excels at high speed cruising)- besides boosting horsepower, gearing is another variable - 4 cylinder Capri's ran a 3.44 rear dif that will drop into your axle housing. I have found that a little extra distributor advance gives my engine improved low RPM response.

    Good Luck!
    Todd Reid
    Last edited: Feb 1, 2021
  12. Bill Blue

    Bill Blue Platinum Level Sponsor

    Todd, you've opened a very interesting chapter. While my car is not a V6, its performance is quite similar. When first built, it wore 165 X 13 tires and a 3.55 rear. Performance was very good. I upgraded to 185 - 60 X 15 tires. The performance, while good, lost its sparkle. Cruise was very good, but it seemed the engine was always caught in a "catch up" mode. After a few months, I swapped the 3.55 for a 3.80. All is good again. Cruise is about 3,000 rpm @ 70 mph and the engine is ready to really go at interstate speeds. A few hundred rpm can make a huge difference.

  13. todd reid

    todd reid Gold Level Sponsor

    I agree - lots of variables, and tire size definitely effects overall gearing. Lots of traditional "hop up" changes to increase horsepower also push the power higher up the RPM scale, which may make the existing gearing less than optimal.

    And you are being modest- your car's performance is far superior to mine!

  14. weaselkeeper

    weaselkeeper Silver Level Sponsor

    I don't have your setup, but if the idea is to retain this setup, perhaps experimenting with different jets/metering rods can help. I'm assuming that timing is correct and vacuum systems are correct and not leaking. Let us know what you find.
    NorCal likes this.
  15. hartmandm

    hartmandm Moderator Platinum Level Sponsor

  16. NorCal

    NorCal Silver Level Sponsor

    Well, that could be the issue.; there is just not a lot hp/torque to be had out of that motor. I've owned a 6 cylinder '73 TR6, '63 AH3000 that would cream this car. My '64 Falcon Convertible I had with a 1bbl 6 cylinder / auto may give it a race.
  17. Bill Blue

    Bill Blue Platinum Level Sponsor

    What is your rear ale ratio? Your talking carbs when maybe you should be looking at gearing. I have a feeling your gearing will nullify any hp you can with a carb change because you need low to mid range torque and carbs will deliver high rpm hp.

  18. NorCal

    NorCal Silver Level Sponsor

    It’s the stock Capri rear/gearing. Pretty high ratio as by 60 mph it’s humming.
  19. Bill Blue

    Bill Blue Platinum Level Sponsor

    Do you ever encounter spark knock? If not, try bumping the timing up about 5 degrees and see what happens. Don't know what a 90 degree adapter is, but the car should not be dog.

    NorCal likes this.
  20. husky drvr

    husky drvr Platinum Level Sponsor


    When NorCal refers to a 90* adapter, he is referring to the riser that sits between the manifold and carb. If you'll note in his engine picture, the carb is sitting about 90* to conventional carb orientation for a v6.

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