They think it is the only cam that can pass emissions. Since a cam is not an
"externally visible" mod, I'd suggest a custom cam that fulfills the needs of
emissions legality and has hotter specs. The #1 biggest determination of
a "clean" cam is overlap. The best known spec for this is .050" overlap.
0* @ .050" is basically the benchmark for passing. Another # is ~30* @ .006"
(same as E303 cam) which is very easy to beat with hotter cams, since the
"E" cam lobes are very lame in ramp rates. There is approximately 61* difference
between the .050" duration and the SAE advertised spec, 281* @ .006", and
Ford's .003" spec is 282* from what I have gathered... there are many nice
lobes that have less advertised duration but the same 220* @ .050" and many
have more lift too, and will easily out-power the "E" cam.
I'm a strong advocate for custom cams if you could not already tell