Perhaps the flow increase outweighs the timing pulled on a TBI engine
I believe this to be accurate. Even if I do have timing being pulled, and I doubt it on my truck (I do have a lot of experience with tbi 350's, never owned a vortec), the increased flow gives it more get up and go. The only time I seemed to have less power was in the middle of summer pulling a trailer at high altitudes up a big hill. My retarded high 3.42 gears don't help.