[Steve C.]

The Crane example mimics these numbers:

60919 approximate duration average 286*/295*@.006”

RA4 grinds (SPC-8 Melling all ground by CMC)

292*/303*@.006”.

Subtracting the 231 duration at .050" tappet lift supports that Butlers cam is more aggressive with the lower intesity number.

When searching the numbers will vary all over the map but here are some examples for a hydraulic flat tappet cam....

Key Intensity Guidelines (in Crankshaft Degrees)

60 to 70°: Mild to factory stock. Lazier ramps, easier on the valve train, excellent longevity.

50 to 55°: Moderate street performance. Good mix of vacuum and power without requiring extreme spring pressures.

40 to 45°: Aggressive. Yields quicker throttle response and more area under the lift curve for top-end horsepower.

Below 40°: Highly aggressive (often seen on racing or solid lifter profiles); this territory can cause valve float or severe wear on a hydraulic flat tappet if spring pressures aren't perfectly matched.

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