Well the pump jets are not as simple to do as the a/f jets are. There is a single barrel jet sitting in the bottom of the fuel bowl that just unscrews. So you need to take the top of the carbs off.
Theoretically the carbs come stock with 2.0's. That means a 2mm orifice.
I've dialed them down to .5's but couldn't start the car the following morning when the engine was cold.
With the .5's there was absolutely no loss of power driving the car. Strange, I know, but this is where I'd get "lectured" by Jim that this was as close to a fuel injection system as you could get with carbs and that's why it worked with the pumps almost locked out.
In my view, the ONLY value of the "stock" 2.0's is for cold starting.
As far as jetting goes, I've run mains all the way down to 125 fuel and up to 175 fuel with the corresponding air corrector for each fuel jet change.
That ratio that still holds true. It is the proportion of 140f to 160a. You have to chart those to see what it means. The proportion is the critical factor.
When I came to that conclusion it was Jim's opinion that it is WAY to heavy. I disagree. The plugs are a nice dark rust brown color.
I do not see the difference between F5 and F7 tubes. MAYBE the F5's are cleaner? They seem to be more important in a 289 set up. The Cleveland doesn't seem to care.
My driving is street driving. Perhaps it is more important under full racing conditions to get these exact? That I don't know.
The plugs were cleaner with 125f but power did drop off.
Testing 170f on the street, there was an immediate increase of power.
Now I did this all without an a/f meter years ago so I do not know what the a/f numbers actually read but I do know what works since I've been running the carbs, on and off to be honest, since 1978 and it was INGLESE that helped me set these up.
The ENTIRE issue with the IDA's is that the idle is next to impossible to lean out successfully. That's what pisses me on the set up and I will keep trying.
You can actually measure the crankcase pressure if you want to go to that hassle. You don't want to excede 12 inches of vacuum. That can be read as a negative number on a pressure gauge if you have one that can show plus and minus.
The racers that would talk to me on this seemed to be happy with 10 inches. Some stated they were still using the exhausts to create it and that number was around 6 inches.
So what a good number is, I can't answer that but I'd speculate that with Webers on this engine, you want the highest number you can get without sucking in the oil seals on the crank. That appears to be the 12 inch number which would explain the 10 being more desirable because of the safety factor.
IF by some chance you are at 12 inches now, you can bleed some of that off by provide a vacuum loss (drilling a hole) at some point in the pcv system. With this Weber set up you have to provide one somewhere. If you were a plumber, you would call it a vent and you could compare that to needing a vent on the gas tank.
For you, since you are already plumbed into the crankcase, a simple pump jet change to 1.0 will probably be helpful.
I had the thought, but never tried it, that you could use one carb as the starting carb with 2.0's and drop the others to .5. I get lots of weird thoughts so like the Warren Commission having to come to a decision after interviewing hundreds of witnesses pick a number on how many assassins there were that day in Dallas?
1.0's are working for me still. Oh, don't be surprised if the pump jet in all the carbs don't match. I've seen that a lot out of new stock carbs, and it doesn't effect anything but I'm running 42mm "chokes". 37's will show richer with the same jetting.
Oh...the progression holes. All the third hole does is theoretically eliminate that flat spot that you feel in the 2800 to 3200 rpm range.
There is a brass screw plug in the side of the carb. If you take the carb off, remove the plug and hold it to the light, you will see them at the end of the "tunnel".
They correspond to the notch that you see in the throttle plate. I think they are #72 drill size but you need a numbered drill set to measure them. All you do is "about" in the middle between the two existing holes, use a "pin vise" and put a third hole in between them. That roughly corresponds to the 3000rpm transfer point.
The "transfer point " is when the mains start coming in. Up until that point you were running on the idle system.
It is easy to do. Anyone can. No need to replace your two hole carbs. Just add the third. It does help a lot.
Totally confused yet? I did try my best! I have to rest now. My fingers hurt from typing.