Got an option on a p-90a head. First time I've ever heard of one. I't a hydraulic unit missing 1 rocker arm and pivot. (rocker arm looks similar to the ones on any other Z head). Saw it at the machine shop where I had my work done sooo.. it had a fresh valve job and resurface. Guy wants 100 bucks for it. My questions are, is this a desireable thing for an L-28 and where am I gonna find a replacement pivot. So far I've found out this is from an ' 83 turbo and I bet it runs real quiet.