This is my opinion but why stuff around changing heads, rockers, cams etc
Get your existing cam reground to whatever specs you want, port match the head to the manifolds or get it ported if you want, add decent carburation/exhaust and go have fun.
This is what I did with one of my 5ks - Wade 169 grind cam, 3k-b carbs, extractors and 2" exhaust (plus a few other things 😉 ). This engine would spin to over 7500rpm all event with bursts to over 8000rpm where the tacho stopped. Without the issue of adjusting valves all the time.