Help with my first engine build (5.9 Magnum)

Also a sunken valve seat lowers your seat pressure. You can overcome that by shimming the springs. It also increases the installed height. It also throws the rocker geometry off. A cheap spring height gauge and a cheap set of vernier calipers would help. Your installed height is going to be all over the map. It’s a personal decision, are these heads going to be used for a longer term? Answer is yes, I would have them machined. If you are going to go bigger in the next couple of years? You could shim the springs and live with the geometry. What rockers?