Going by the numbers can be a problem if the rockers are not all from the exact same year. Chev used the same number on different rockers in different positions in different years.
The best way I have found is to first separate the intake and exhaust rockers, then lay all the rockers on there side. You will then look at how close or far away the valve end of the rocker is to the table. That way you know which are left and right rockers. After that you can follow the Shop Manual arrangement diagram or this
LINK .
