Nice looking set of heads for the cast iron factory type of guys.

nail head valves vs tulip on track was worth .20 and 2 mph in a 340 stocker, on flow bench was 8 cfm per port better times 8 = 64 cfm total. just food for thought. john is right ports look very big,
That is pretty close to exactly what I observed back 30 years ago.
I just did not mention anything about it for many years!