Make sure you install some better valve springs along with those 1.6 rocker arms. My personal experience with the LT4 rockers on a stock '97 LT1 was valve float at 5800 rpm. After installing LT4 valve springs the valve float went away but the h.p. numbers were hardly worth it. The dyno showed a 10 h.p. max increase. I thought it was hardly worth the effort.

You need to change the cam at the same time to really feel a difference.