Hi' guys want know if cilinder pressure changeswhen cam is set straigt, advanced or retarded.or when are whith low or high duration. thanks.

Yes it does.It's lower with more duration and overlap, that's why you can't run a big cam in a low mechanical compression ratio engine. Little change when advancing or retading a cam a degree or two.

Advanced = more cylinder pressure, retarded = less cylinder pressure, but as Gary mentions , not by much. Changing the cam timing in my 427 from 0 to +6 took DCR from 8.5 to 8.6