I know it's not exactly what you asked but, I did minimal testing & it was long ago on the superflo on mopar stuff but getting more lift with a stock port 906 isn't going to do much, I don't think. They are pretty flat from about .460 or so up to .525 lift I checked them to, at least on the intake side. I wouldn't change 1.5 to 1.6 & expect much more horsepower.