Slant six idles rough

You see that vacuum device bolted to the carb, on the left there? It is called a choke pull-off. It's job is to pull the choke open, just a little bit, as soon as the engine starts. It has to be connected to full-time manifold vacuum. How far I do not recall, but I'll guess 5/32

So lets see how this works;
With a cold engine, and not yet running
1) the flapper valve in the exhaust pipe should be closed
2) you step on the gas pedal a couple of times. This shoots raw gas into the intake, and the choke pushrod closes the choke all the way. This action causes the throttle to open, but when it closes, it is held open by the fast-idle cam. The engine is now ready to start.
3) you engage the starter. With the choke fully closed. the cranking engine should be pulling huge amounts of fuel out of the floatbowl and spewing it all into the intake, this is normal. The engine catches and begins to run.
4) because of the larger than normal throttle opening, as soon as the engine catches it will rev up. And when it does that, the choke pull-off is supposed to open the choke, to prevent flooding. Now, the closed flapper valve, is piling up hot exhaust in the log manifold. Within a minute or so, the rpms are rising too far, so you kick the gas pedal, and the throttle should fall to a slower rpm. Within about three minutes, that heat in the log, should cause the choke rod to retract and fully open the choke. That heat will also come up and heat the plenum floor under the carb in an effort to vaporize the fuel.
5) After about three minutes, if everything is working right, you can slap the gas pedal again, to put the throttle onto the curb-idle screw, and then you should be able to put it into gear and drive away.
6) that's if everything is working the way that the factory engineered it to...... over 50 years ago. And if you set the carb according to the FSM.
But 1965 is a long time ago, and at just 130 psi cranking compression, your engine is no spring-chicken. So, in all likelihood some adjustments to the factory specs may be required, but
you gotta start somewhere, so
Step #1,
start with the FSM specs.
>And start by checking the fuel-level in the bowl.
Nevermind about your new carb being new. New just means new.
>Then set the valve lash. I use .013 on the intakes, and .023 on the exhaust. Others use a lil less. I tell you what, set them to 0.013/.023 and get it running right and later you can try tighter. I set them at the garage temperature of about 68*F. Now the thing about slanty rocker arms is they are softer than the valve stems and after a few years will have ruts wore in them. So if yours have ruts, then you will have to cut your feelers to fit inside them, else your lash will go thru the roof.
> next is setting the timing. And that starts by proving TDC on your damper is still, all these years later, TDC to the #1 piston. To do this , you will need to buy or build a piston stop.

I know yur thinking that all this seems a chitload of stuff to do just to cure a "rough idle" and you would be right. If your car was in my driveway there is a good chance we wouldn't be talking about any of this. But because we are separated by hundreds of miles of space, all of us are just guessing until we have a baseline of where you are at.

If I told you to go out and blow your idle-bleed jet out, would you know what I was talking about and how to do it? If yes and yes, then go do that, and tell what happened.
If I mentioned that your emulsion tube might be plugged, would you know what to do about it? If yes, and blowing out the airbleed did nothing, then go clean your E-tube.
But if neither produces a change then go to step #1, lol.