imagine sucking in through a paper towel tube then blowing out through a straw. Makes sense that if a stock exhaust valve is not capable of scavanging it well enough stepping down the lift on the intake side might balence it out. As said above Ive heard of it on sbcs but that was in a rediculesly monster valved high revving high compression sbc not in a street motor.

I agree with your disbelieve tho. I wouldnt mind knowing what exhaust set up was on the car in question and how much REAL gain there was.