Cams How do you choose one?

Great chart in general
note the wider power band with shorter cam and if not big heads the longer cams have an even smaller power band
calculate rpm drop at shift and cam no bigger
also small heads limit upper durations or give a narrow power band think stock heads and a big cam for certain class racers very unstreetable
and too big heads limit lower durations think Boss Ford
and 340 heads of this build- to big a cam for the heads and compression