Avs secondary tuning ?
- the secondary butterflies shouldn't be open at cruise, even at 80 mph.
- vacuum opens the air door, but the air door allows the vacuum to first start the fuel flow syphon
Exactly. This is not a vacuum secondary carb. It has mechanical secondaries, just like a Thermoquad or a quadrajet.
The throttle opens the secondaries and when the air speed is high enough to overcome the weight of the air door and the tension spring, it opens and you have air flow through the secondaries.