The .050" duration is a better indicator of how hot a cam will feel than nominal duration. The stock cams are really mild (compared to V8), with 220° and up actually making more peak power.
IME most aftermarket cams' .050" duration can be approximated by deducting between 30° and 40° from the advertised intake duration (half that from each end of the timing figures). Hot cams with faster ramps should take off closer to 30° (the above Crower is 32°) and mild cams with slow tappet movement more than that.
