I don't see the problem with my earlier post about the flow rates. According to the link you just posted, Rod, the average flow rate for AFR, Brodix, E-Brock, GM iron heads and many others range from a low of 240 to a high of 293. That average is based on lift amounts up to 800.
That data is consistent, in general terms as to my previous post, that any head that flows 300 or better is a terrific head. Stock big block GM heads, surprisingly, aren't significantly better than big block Ford heads.
If were comparing modern heads, like AFR, the Blue Thunder FE heads, "worked" flow 350-400 cfm.
Avg. Flow
298 276 270 262 266 247 240 270 262 273 260 263 278 275 276 272 293