Right or wrong, I shoot for a static CR that gets me around 180 psi cranking and then dial in DCR with duration.
Yes your right I think the cranking compression target is 180 for aluminum and 160 or less for iron! That said I have been keeping my cranking at 195/200 with 93 and been fine but some other factors are a richer mixture and 4000 stall (this year a 5000) so the motor is up in RPM's before it totally loads and as RPM rises octane requirements lower!
A motor that will ping slightly at 2500 on load will not ping at 4400.
