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40 Deluxe · 11-10-2023, 11:51 AM

[QUOTE=Grumpy Rick;2267808]My '55 T-Bird came with an assortment of parts. Two teapot carbs and an Edelbrock 1406 600CFM (AFB copy)carb which was on the car along with the original distributor still being used.

Since the Edelbrock has an air valve on the secondaries, your engine will never get 600 CFM if it doesn't need it. The secondaries only open enough to meet engine demand, so in normal highway driving they never open and only open partway even at full throttle (unless you have a high RPM race engine).
Get the Edelbrock manual and put the factory jets and metering rods back in if they have been changed. Check the float height and set to specs.
Use a tach to set the idle screws. Adjust one at a time to get maximum RPM (with closed throttle) then set idle speed to specs. Readjust mixture screws if needed. One at a time turn mixture screw in to drop about 20 RPM each. This will give lean best idle for both better fuel mileage and low emissions.
Forget any bogus vacuum gauge nonsense when setting idle mixture or timing!

11-10-2023, 11:51 AM	#8
40 Deluxe Senior Member Join Date: May 2010 Location: now Kuna, Idaho Posts: 3,783	Re: Teapot CFM? [QUOTE=Grumpy Rick;2267808]My '55 T-Bird came with an assortment of parts. Two teapot carbs and an Edelbrock 1406 600CFM (AFB copy)carb which was on the car along with the original distributor still being used. Since the Edelbrock has an air valve on the secondaries, your engine will never get 600 CFM if it doesn't need it. The secondaries only open enough to meet engine demand, so in normal highway driving they never open and only open partway even at full throttle (unless you have a high RPM race engine). Get the Edelbrock manual and put the factory jets and metering rods back in if they have been changed. Check the float height and set to specs. Use a tach to set the idle screws. Adjust one at a time to get maximum RPM (with closed throttle) then set idle speed to specs. Readjust mixture screws if needed. One at a time turn mixture screw in to drop about 20 RPM each. This will give lean best idle for both better fuel mileage and low emissions. Forget any bogus vacuum gauge nonsense when setting idle mixture or timing!