I have a 67 dart, and i just replaced the carb with another stock one from a 74 dart swinger. everything works fine, but I'm getting a lot of hesitation, especially in 1st and 2nd gear. when I press the accelerator, i hear a sucking sound, then about a half second later it revvs up. If I put the gas pedal about half way down,it sputters, then revvs, and sometimes when i floor it, it dies. Note:It continues to do this when the engine has warmed up.

Are the carb to manifold nuts tight? I had similar symptoms and it was the nuts came loose.

Since a '74 carb has more vacuum ports, are the unused ones capped off? If your mounting bolts are tight (you did install a new base gasket-- right?) then it sounds like a vacuum leak. While you at it check ALL the vacuum hoses. They should be pliable. If they are stiff, then splurge on some new ones. Don't overlook the PVC hose.

The accelerator pump is another of the usual suspects - make a pitstop there. Good luck.

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