Has anyone ported stock magnum heads and have the before and after flow numbers .???

I can tell you in MY experience on the china magnum head, not the good "EQ" version of old, 270 @ .500 is not to difficult, it's all valve job, (2.02) bowl sizing, guide shape, and some pinch trimming. Not what I'd consider "fully ported" but more of a well executed bowl and valve job. Not much point in doing that to a oem magnum that does and will crack. Yeah they run cracked, sometimes a long while. But eventually that crack works into the seats from my experience, and they go in the dumpster