My 416 has a small miss at constant rpm. Especially noticeable between 2500-3000 rpms. It has msd billet dist that's locked out. Msd blaster 6 al and wires. Ngk racing prov 7 plugs,and Quick Fuel 850 carb. It doesn't stumble on acceleration.
I recently changed power valve to 4.5 due to running...