With the econo W2 heads, only the rockers are unique. The reason they were called "econo" heads, was solely due to the fact that they use the same valves, springs, retainers, and rocker shafts as standard X/J/O/U heads. So it would be way cheaper to put a complete setup together.
I'm not 100% sure, but I believe you can even get away with using TA rockers and shafts instead of the W2 specific rockers. I could be wrong on that one though.
