I have a pair of Coon SOHC heads that I bought from Jay, one of the sets that he got in his second batch. I brought them to Brian at R&R Performance in Spring Lake Park Minnesota, the same person Jay uses, since I knew by that time he had some experience working on Jay's heads. At that time Jay had found the Ferrera light weight valves were considerably lighter than what he had been using, so I bought a set of those. Further testing by Jay and Brian found the light weight Ferrera valves are not the best choice for max flow though, but I decided to stick with them anyway. Brian at R&R did the valve job and just a minor cleanup of the port under the valve seat, he did not do any other porting on my set. They are not "as cast", but not too far off. Brian flowed my heads, he also provided the flow figures for my heads but with the Manley valves he and Jay had found flowed much better. One thing this shows is head flow, like everything on a race car, is all about the complete "package" and not just the head casting itself. Jay has covered this topic in the past in one of his SOHC builds, he probably remembers more of the results they found. Here are my flow figures:
Intake
Lift .100 .200 .300 .400 .500 .600 .700 .800
Ferrera 77 158 225 280 324 345 354 357
Manley 80 163 239 312 361 381 385 386
Exhaust
Ferrera 53 112 175 208 235 260 280 293
Manley 56 111 174 219 260 285 296 303