thats a lovely setup Benny. Strange Nissan only used cast iron camshaft towers in most FIA heads.

That porting shots could have better valve guide ramping from almost the start of the top of the port where a splitter bridge can be used to spread the inlet charge to the sides rather than form an eddy around the valve stem much like the splitter on twin port inlets. I think it was Audi or Renault that did this on some 2 valve heads.