I've never heard this, but, if you can get a 1.6 rocker ratio for the engine, know that a higher ratio has a direct impact on HP output. Not much, but it is the extra lift that alows the head to breath in more and exhaust out more. The increased ratio also has a effect of giving the cam more intencity and a ever so tiny increase in duation.
Being that the cam is opening at the same time still and will allways will, it is the rockers increased ratio that lifts the valve (Ever so slightly) quicker and moving the valve off the seat (Ever so slightly quicker) that the duration @ 050 is increased.
Cost vs HP delivered worth it? Probably not, but then again, every little effort towards the goal is a good one and they do become a simple math equation of, item A + item B + item C = more power. Then add on D + E + F ='s more power.
Bang for the buck diminishs after certain add on's. But the effect ad's up. While thr rocker ratio change by itself is not alot on a stock engine, it becomes more of a power added as the engine is more and more modified.
On a stock engine, lets just say it is worth 5 HP. On a mild modified engine, it'll be worth 15 hp. On a very worked up engine, it'll be worth 30 hp and so on and so on. And now it is up to you.