[rdorman]

I had this huge response all typed and the *&^*ing network logged me off!

Pull the carb and check the throttle blade to transfer slot relationship at idle. You want .040 to .065 of the transfer slot showing below the throttle blade. If you have more close the primary throttle blades to some where in the middle of that range and open the secondaries by the amount you just closed the primaries.

Couple of items. If the tranfer slots are different lengths, this should be replace by Holley under warrenty. There where a few like this. If the secondary idle speed screw is not covered by the intake, remove it and replace it with a screw that can be adjusted with the carb on.

Set the speed by the secondary. Some reasonable speed. Not like I am found of doing, so slow that it lopes really bad! Small adjustment can be made from this base setting using the primary idle speed screw. While you have it off, see how much you have to turn that screw before you either have less than .040 or more than .065 showing. Not a whole bunch is it?

Set the idle mixture for highest vacuum at the leanest setting. It the RPM increases, bring it back down to your base setting before comparing vacuum ratings.

Set the float level. Note if the float level rises as you increase RPM. If so the so is your fuel pressure. 1/32" per psi if I recall. If you can't seem to set the float level with out the fuel pulling out then you can be sure that you need a new needle and seat and are perhaps running way to much pressure.

This all but cured every part throttle, lean, hesitation, cruise, etc issue in my car. Bascally, many of the same issues you are describing! You can also drill the blades but try this first!

This is a fraction of my former response but it is time to go home!

Rick