replacement heads

good morning . . .where ever u are. . .

i just got a set of 45 heads delivered from Flatland Motorcycle/45Parts depot.
i ordered #5 heads beacause i was told the #6 heads gave me 12mm clearence and i have one valve that measures close enuff to that to cause my nervs to twitch.
the #5's have lots of room for the valves.

my question to the forum is. . .what sort of performance difference should i expect to see with 5's compared to 6's?

debateing about getting the 5's shaved. not sure it is worth it.


D~~~!