Looking for a shop to rebuild my zx head new cam port and polish make it better.

thanks.

I don't think I've ever heard of a P89 cylinder head, most likely a P79 if it came of a ZX. 

In my experiences call the oldest machine shop around and ask them if they'll work on an "L series Nissan straight six".  If they've been in business for many years they most likely forgotten more than we know about those heads.  I'd guess between '75 and '84 plus the years until they crap out, maybe 1994, they've worked on hundreds if not more.  I had to research to re-familiarize my machine shop guy as to what I needed done.  They were before computers and such so the more info you can supply the more likely they'll accept your head.

Call around...you'll find someone that is interested in doing the work.  You might even find a cylinder head shop that would take it?

Good luck!