Not an expert myself but will share some notes that I have gathered from various internet sources and emails/calls with Jim Inglese. I am running a Redline manifold on a 347 with Weber 44 IDF carbs.
Weber 44 IDF Setup
Main jets – 145
Idle jets - .65
Emulsion Tubes – F11
Air Corrector – 175
Floats – 11mm open without ball valve being depressed
My timing is all in early before 3K RPM at 38 degrees BTDC and roughly 20 degrees initial.
1. With motor off, Disconnect linkage between carb left and right side
2. Back idle speed screws out till not touching, then turn in ½ turn on each bank
3. Set idle mixture screws to ¾ or 7/8 turn out from seated
4. Start motor
5. Synch carbs on each side using only adjustment screw on linkage between carb banks
6. Reconnect linkage between carb banks
7. Adjust linkage between banks till left and right side banks are in synch then lock down linkage
8. To set best lean mixture, for each cylinder
a. Turn idle mixture screw out 1/8 turn
i. If idle speed increases stop, if not repeat 8a till idle speed increases then stop
ii. If idle speed decreases or does not increase, turn idle mixture screw in 1/8 turn till idle decreases then back off 1/8 turn
b. Repeat for each cylinder
9. Check each spark plug condition after driving for lean or rich, adjust each cylinder as needed. 1/8 turn in on idle mixture screw if rich, 1/8 turn out if lean.
10. If you have a flat spot during transition from idle to main circuit, back each idle mixture screw out 1/8 turn.
I can tell you I spent weeks messing with different idle jets only to discover what a significant impact timing has on these setups. I have since gone to a locked out MSD Distributor at 40 degrees and control the timing curve with an MSD 6AL2 Programmable ignition box. Too much or not enough timing will cause a stumble thru the transition phase that you will swear is an idle jet problem. My car is very docile and predictable at low RPMs and all thru the transition curve to 3K RPM with light throttle and will climb thru the RPMS quickly with heavy throttle. I have found with my setup I do need to run slightly rich or I will get lean pops in the sidepipes under light acceleration and deceleration.
Some web links for helpful reference:
http://www.redlineweber.com/html/Tec...t_controls.htm
https://www.racetep.com/manufacturer...ber-carbs.html
https://www.gt40s.com/threads/weber-...youtube.32276/
http://www.timsroadster.com/html/tuning_webers.html
Ignition Timing and Webers
https://jiminglese.com/common-questions
https://jiminglese.com/weber-tech
https://www.gt40s.com/threads/weber-help-please.41056/
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