Easy question. I'm trying to expose less of my primary idle transfer slot. The idle screw is not even touching. I've adjusted fast idle all the way out and its not touching. Yet I still have a lot of primary transfer slot showing. what am I doing wrong. TIA John

You have to take the carb off. There is a little adjustment screw that is only accessible from the bottom, that setting determines the maximum closure of the blades.

Are you sure that the fast idle cam is all the way off?

That screw all the way on the bottom of the carb is for the secondaries. I'm trying to adjust the primary blades.

Disconnect the linkage,if the idle screw is not touching the arm,something is hanging up somewhere,probably around the fast idle cam.Also,the Holley has a tang to adjust fast idle,not a screw regardless of model unless it has a solenoid and you should know how to disengage that.

OK, my primaries arent closing because the linkage is hitting a huge bracket near the accelerator pump lever. The bracket has a big round hole in it almost 3/4" diameter. (I bought this carb aftermarket). Can I just remove that bracket, it doesn't seem to be serving me any purpose. It's probably for an auto trans application.

Picture would help but if it serves no purpose,remove it.

hi
that bracket is most likely for a dashpot !

I removed the dashpot bracket and now the primary blades close a lot more. I got just a perfect amount of primary transfer slot showing...it looks like a square.

Some of the 4160's don't have a screw for the secondaries,the top one I pictured is a 4738,70 RR 4 spd.no secondary screw.

UPDATE: I removed the dashpot bracket and now the binding is gone, so the primary blades now close a lot better, closer to a perfect amount of primary transfer slot showing...it looks like a square.
Yesterday - I opened the secondary blades father using the adjustment screw on the bottom of the carb and took it for a ride.
The car now runs better than ever before...the idle adjustment screws are giving the best vacuum readings...much closer to the correct 1.5 turns out, rather than the incorrect 0.5 turns like I had before.
So I know thing are better now, BUT...the problem now is, the idle is too high... with the idle screw not even touching.
So, I guess I went too far with adjusting the secondary screw. Iwill fix this.
(I could retard the timing but I dont want to do this right now).
Question: Is the objective to get the car to idle just right with timing adjusted just right but without the idle screw touching the primaries at all? Or is it OK to have the idle screw touching a little bit?
Finally, what is the best power valve for a 3310 with 16-18 degrees idle vacuum? 8 to 9? What jets should I be using for a stock cam 440?

The idle speed screw does what it says,adjusts idle speed and with your vacuum,the original 6.5 power valve is sufficient.

vacuum leak?

Here it is, the Holley Numerical Reference.
It'll tell you what your carb came out of the box with.

You are right about the idle setting. The standard idle screw setting for Holleys is 1 1/2 turns out from lightly seated. It shouldn't be more than 1/4 turn on either side of this for a normal street engine at close to sea level.

Study the Numerical Listing.
For the 3310 there have been at least 11 dash numbers. Most of the 3310s came with 72 primary jets. Holley carbs have usually been close out of the box. If anything they usually were a little rich. The secondary plate number can be referenced to equivalent jet sizes although it usually doesn't have to be changed. The combo of the plate size and the power valve rating take care of the top end of the fuel curve. At wide open throttle the exact A/f ratio isn't as critical as long as it doesn't go lean.

I'd start with 72s in the front. Run the carb and see what it feels like.then I'd start decreasing jet. Holley says go down two jet sizes at a time. So swap in 70s. If it still drives OK you may want to swap in 68s, but that is pretty far off. If the jet is too small the engine will exhibit lean surge at steady speed. Some people disconnect the secondaries while working on the primary side. If the carb shows lean surge with stock jets then you'd want to go up two jet sizes. Once you get close you may want to fine tune with a single jet step.

If you have an A/F meter so much the better.

I live at altitude, between 3400 and 5290 feet. On my first carb I had to go down 6 jet sizes before it stopped fuel fouling the plugs. I was really surprised when I went down to Phoenix in the middle of summer. I expected to have some trouble with leanness. Surprise! Everything ran fine at 110 degrees. Looking back on it I imagine the density altitude was sky high so my jetting worked.

R.
Others will have much more advanced answers for you.