Originally Posted by Brian Carlton

It's difficult without a Mityvac, but, it does appear that the VCV is working correctly.

You can adjust the VCV if you get a Mityvac.

However, your results via adjustment of the modulator seem to indicate some success as well.

The orifice is a very small plastic nipple that is easy to miss. Look for a round piece of plastic........just about the same diameter as the vacuum hose.........in the vacuum hose line from the main vacuum to the VCV. If the orifice was slightly larger, the rate of vacuum falloff with increasing throttle position would be lessened.