Well I hope you have better luck than me.

1) I connected the vacuum gauge up to the right side port (driver's side) of the carb and started the engine. At ~700 I was getting 15"Hg- pretty much what the left side was doing. That blows the idea of trying to use the other port....

2) I resealed the right port and connected the gauge up the left port, then with the engine running I started backing off the idle speed. The engine died around 300rpm and during the time I was turning down the idle speed screw the gauge still read around 15"Hg up until around 350rpm where it dropped off to 5"Hg.

Is anyone else out there getting similar readings from their Edelbrock 1405/1406 that aren't encountering any engine issues?

Robert- I'll wait to hear from what you find out and if your carb is giving a good reading then I'll probably have to call Edelbrock Tech Support and find out what they think....