The Lunati catalogue states the below in regards to valve spring pocket clearance; but what it doesn't list is how large a clearance is acceptable before spring cups are required. Does anyone know??? My spring o.d. is 1.5"

from Lunati catalogue:
"Valve spring pocket clearance is the gap between the
inside diameter of the valve spring pocket (or cup, if used)
and the outside diameter of the valve spring.
• Too much clearance will result in the spring “
dancing” around in the head, which “beats up”
the spring mounting surface and the spring itself.
If this is the case, a spring cup may be used. Additional
machining of the spring pocket may be required to
accept the spring cup."

thanks.