87 carbed 302 too rich?

Discussion in 'Fox 5.0 Mustang Tech' started by djcfiveoh, May 30, 2011.

  1. As a Mustang guy, I now have a CJ5 project that is Mustang powered.
    I have a 87 302, w/Edelbrock 1407 on a Performer 289 intake. Has a MSD 6600 ignition, 8250 coil, and a magnetic pickup in a double vacuum advance distributor. Hesitates/bogs at initial load. Idles and runs fine in the garage.
    Sells rich when driving. Have adjusted idle jets and speed, readjusted timing to 10 BTDC, tried both full vacuum and timed vacuum on advance. With full vacuum on, idles around 22 BDTC, runs up to around 34.
    I am yet to check fuel pressure. But, it is not flooding.
    I dont yet know which distributor is on the engine. I have to look it up yet.
    NOt the big blue cap. It is small, spring clipped cap with double vacuum advance/retard.
    Just thought I'd put it out there to help with direction.
  2. 750 carb sounds too big, but i would tune by changing the metering rods, they are easily changed by removing the two small plates on top with a torx bit. It could actually be too lean, too much air because carbs to big. The metering rods have two step diameters, one for cruise, the other for power, that fit inside of the jets to control the flow of fuel. find edelbrocks metering flow chart in the instruction manual and go from there.
  3. +1 on that. A smaller carb will likely make your problems go away. Try to borrow a vacuum secondary 600 from a buddy and try it if you can.
  4. Carb too Big

    A 650cfm is MORE than enough to feed what you have.
  5. Read the plugs, which means pull them, and look at the color. Very light tan is ideal (small gas deposits). Very white means too lean. Black means rich. Unless you're running lots of RPM with a large cam and exhaust, 750 is too large, and 600-650 sounds right.
  6. Same issue & fixed it

    Same setup in my Jeep. Set your float level. Edelbrocks are really sensitive to incorrect float levels since it has everything to do with A/F delivery. If your motor has a cam and heads, (Higer flow rates) a 750 will work, but not as well with a smaller carb. Heavy load and WOT is where you will loose performance.

    Also check the color of the plastic at the plug on your ECM. This will affect the Ignition and appear to be a carb problem. You need the blue one on a Duraspark 1.

    Finally realized the full potential of mine when I switched to a Holley 670cfm.

    I will be selling my setup as soon as the EFI goes on.

    Holley 670 cfm, Wieand Stealth intake, Duraspark 1 ignition with ECM, Holley red electric fuel pump and engine bay harness for all connections.