I'm running vacuum-secondary 390's on a mild-cammed SBF with a Weiand dual-quad tunnel ram.

There is a definite lull, almost a half-second stumble, between the time the secondaries open up (3000 rpm) and the time the car goes ape$#!+ (about 3500rpm) sort of like the car is taking a deep breath before sprinting. I have been told that this delay is typical of tunnel rams, and is a function of the amount of distance between the carbs and the cylinders.

Is this the kind of hesitation you're talking about, or is it missing completely?