Need some advice. I can't get the motor in my '63 falcon to idle ... at all! Have tried two different carbs (holley 600 & edelbrock 600) and both exhibit the same problem. Car starts with choke closed on fast idle and runs seemingly fine. When I kick it down after a bit the motor will not hold an idle and will die. It only keeps running if i pump the throttle which to me indicates that it is running off the accelerator pump "squirts".... otherwise it dies out after a few seconds. Both carbs have been rebuild, floats set according to the guidelines and mixture set per initial instructions. Any suggestions on where to go next???