Quadrajet on a Slant Six

Well, Dave, you're right. A big carb doesn't make a small engine powerful. My goal has always been to have a fun-to-drive, fuel efficient car as I do most of my driving on the highway. If I really wanted more power, I would have done the same as you and dropped in a 360 a long time ago. The power I have with my engine is plenty for what I need. Like you said about your slant six getting attention at car shows, I find V8 cars to be a bit too common. To each his own.

As for why I didn't use the conventional 390 CFM Holley, it's because I liked the design (and price) of the Quadrajet better than the Holley. The (oversized but free) AFB I was using previously worked OK for the most part but it didn't handle the fuel sloshing well enough on left turns. The fact that it can properly meter fuel on a small engine like mine is what I think is important. Incidentally, the Quadrajet would also have never fully opened on the Chev 350 that it originally sat on either.

The part about air flow opening the secondary doors is something I never quite understood. When the doors are closed, there is no air flow. Therefore, how can no airflow cause the doors to open? However, when the secondary butterfly valves open, the pressure in the secondary barrel below the door is less than the atmospheric pressure above. This difference in pressure is what I thought caused the doors to open. The greater the pressure difference, the greater the amount of opening.