The ZDZ rods are all aluminum --at least all I have seen - original were cut from bar stock - current are formed.
Porting is interesting subject - I was frankly amazed when I looked in, at the porting on the new ZDZ50 - also the latest 210-
-The new MVVS looks to be from same school of thought.
Way back when - the new Perry porting and the Scneurle engines wer "assumed" to be rpm engines and the old simple square cut ports were "torquers" - because they ran at low revs.
The old stuff was just slow .
I LOVE these new designs - -I would have a hard time accepting less.