Join Date: Jan 2000
Location: Santa Anna, TX USA
If I remember correctly, the quadrajet secondary fuel supply is supplied from two small holes at the back and bottom of the fuel bowl. If the carb has any trash in the bottom, it will pretty easily find its way to the supply holes, causing a lean condition when the secondaries are kicked in. Also, even tho the secondary throttle plates open when you "mash the gas", the air flow is actually controlled by the "flapper plates" at the top of the secondary bores. If the spring rate is not correctly adjusted, the plates will open too quickly, causing a severe bog, or not enough, giving less performance. A starting spot would be to hold the throttle open(engine off), and push the air valves open. They should gently return all the way to the closed position. If they do not, the spring tension probably needs to be adjusted.
68 SS Camaro (377CID, 11.633 @ 115mph)
72 Chevelle (350CID, 13.42 @ 99)
73 Nova Hatchback (under construction)