One thing you need to learn about cams is that the only real way to pick one is lift. All manufacturers measure duration differently. Valve float is more a function of your valve train and springs and rpm,not cam duration.
I would never ever pick a cam by lift. That would be for someone I didn't like.
Crane advertises there rate right on the card itself along with the duration at .050.
Valve float is the valve springs inabilty to control the cam at any RPM. Of course, the limit of the spring will be when the valve floats and you'll know.
Valve float can happen at almost any RPM. Period.
