I just replaced my Tri-Z piston with a YZ 250 piston (83-87). They are basically identical except the YZ has a taller dome, whereas the Tri-Z is almost flat. If you are looking to bump up your compression a bit it's a good option. It will change your squish tolerance so you want to pay attention to that. When I first put the YZ piston in I had a problem with detonation because it reduced my squish to about .030 (I run 50/50 race and pump). I spaced it out to .042 with a copper base gasket and it fixed the problem. By the way, I found a great source for copper base gaskets for the Z. Copper Gaskets Unlimited makes gaskets in a wide variety of thicknesses so it makes it easier to hit your target squish tolerance. Here's a link to their website and a picture of their gasket.
https://coppergaskets.us/