Thought I would share my personal experience with the modified 1.9 rockers from zzp. These will not work on some l32 and l26 heads. The pushrods will hit the heads in some cases due to the bad casting sticking out. I installed them and had major ticking and after pulling them out 9 of the 12 pushrods had a small pea sized mark on them. Also the pushrod seats on the rockers are drilled closer to the head meaning your pushrods will run closer to the head. Needless to say save yourself some $ and time and just do a cam install. I will only cost you a few hundred more and you'll be much more happy.
Here's the damage https://copy.com/Iq2PdZpVh8z0EDcQ
Here's the modified vs stock rocker pushrod seat https://copy.com/3WEjPgz0pdbhOELj
And the dreaded tick they caused https://www.youtube.com/watch?v=05L2L9FMidA