Rocker arm ratios

Hi! I've heard and read (on this site among other sources) that the stock rockerarm ratios is quite alot under the 1,5 they're supposed to be, but both mopar performance and sealed power makes stocklooking rockerarms for the small-block chrysler, the question is - are these true 1,5 ratio or just as far off as the stock ones?

Oh and by the way, what's the difference between a left and right stock rockerarm? What part number is right and what is left? :-s