it would have had to pressurize it somewhere for the gains. the extra airflow for the extra power HAS to be present.

n/a is a very broad term...i've run 20psi out of an S-Trim on an 11:1 SCR motor. and im not talking about this leaf blower boosting 5 pounds or something, just decreases the vacuum, possibly to a point of slight pressurization. didnt look like a big enough blower to feed the air consumption of the 4.3L though, think it made more mid range power then max power.