If you are using new stainless valves, you will need to increase the clearance on the exhaust valves to about 0.025". You can check what you have with a magnet. There will be only a little attraction if they are stainless.
I recently did another motor and used stainless valves and a new grind on the cam. The guy who did the regrind asked me what I was using and told me of a guy who ran into trouble with is Model T. He set the clearances at what the book said but the car didn't run well. Upon investigation, it was found that the cam follower was rubbing the heel of the cam quite hard. They opened the clearance and it stopped happening at 0.025". The stainless valves expand more than the others so they require more clearance. I found his 0.025 to be pretty right.
If using "normal" valves, what Jim says is OK but not less, IMO