Here is my experience with the power valve opening point for a street car;

When cruising in the 14.+ range, a late opening power valve (6.5 and lower numbers) can often result in a stumble with light additional throttle. 14+ A/F ratio quickly becomes 15 or 16:1 under even light additional load without additional fuel.

With an earlier opening point (8.5-10.5), the additional fuel comes in at a more appropriate time and prevents the stumble.

I do agree that when you stomp it (whether at the track or on the street) you blow past the opening point fast enough that it is far less relevant. But can still help or hurt in some situations, so it should receive some attention.

Most of the Double Pumpers I have dealt with have been plenty rich about everywhere, so I would be a little surprised if the OP's DP needed anything more than a bit of tweeking, if in fact his stumble is due to a lean condition.

Just my .