I need to know about cams.

[Jeff Chambers]

Not to nit-pick, but the durations are commonly given at 0.050" lifter movement, not .500".

Also, for roller cams, the roller is on the end of the lifter (not the pushrod) and rides on the cam lobe. Hydraulic roller lobe profiles can usually be more radical (higher ramp rates) than flat hydraulic profiles since the roller is better able to follow the profile. Solid flat & roller profiles can be even more radical yet since there is no pumping action associated with the lifter and they can be forced to follow a lobe with severe ramp rates by use of mondo spring pressures. For example, a high revving solid lifter cam may use spring pressures of 350# on the seat and more than 700# when open where your typical EFI hydraulic roller cam may only use 125# on the seat and 300# at full lift. Obviously, those high spring pressures of the solid cam don't come without some price.