Road Runner Nest

I have a 69 Coronet 500 convertible with a 383 2- barrel motor but now has TTI headers and edelbrock 750 Performer carb and Edelbrock Performer RPM intake. This motor has never been apart and when I checked the compression years ago it was all within 15 # per cylinder. I have an awesome orange box ignition Bug Zapper ignition that will throw a spark 3/4 of an inch no problem. I just tuned it after 40,000 miles and the plugs and cap, rotor looked like new. My question is I don't feel that the secondaries on my carb have ever opened once matter of fact I had a 650 CFM Edelbrock on this when I got it and I don't think they ever opened either. With both carbs I tuned with timing tape, timing light and vacumn gauge after finding true TDC. I tweaked the dwell at the vacumn advance for max performance according to Mopar specs. I had a 400 Magnum 73 Charger with 69 avs from 69 440 Charger and when the secondaries opened it just howled. I have a factory 383 Mag air cleaner on this with 2400 stall and 3:23 sure grip. I think this has alot more in it if the secondaries opened. I feel it is around 100MPH in the quarter by the seat of the pants but I think there is more. By the way as of now I have a factory 2-barrel cam and get about 16 MPG when I don't get on it. Is there a way of adjusting the counterweight secondaries?

Many years ago I was loaned an AFB off of a '67 GTX. The owner had REMOVED the counterweighted air valve.
On my 440, it bogged a little, then flew. I've never tried this on Edelbrocks version, but I'd give it a try.
You'll know pretty quickly if that's your problem! I've heard you can lighten them by drilling holes, or cutting off pieces of the weights, but never tried it. If you floor it from a roll it shouldn't bog much. Let us know what you discover.

One other thing, If you take the carb off to remove the valve, make sure your carb base gasket is properly supported, on some performers there isn't much metal around the carburetor to support the gasket. Edelbrock sells a steel plate to go under the carb, sandwiched by 2 gaskets. A leak here may prevent the valve from opening.