Ah, The proverbial can of worms.
I haven't done anything on my head yet. Right now the plan is stock valve size and just thin & reshape the boss. I want the most velocity at low rpm and I think the volume is adequate for my purpose, a low rpm truck engine. One thing that is said about the 194 head is that by the time you add & un-shroud bigger valves you have a 230-292 chamber head. Twisted6 & CNC DUDE have a lot of experience here. 12 Bolt Tom has done Dyno tests with good stats on higher rpm setups. As far as I can tell there is still some gray area for low end power. It all comes back to the toughest of all hot rodding engine build questions, " What do you
REALLY expect your engine to do?" It can not do everything and each of your components must work together to reach your goal.