Werby,
I copied this directly from the you tube text:
387 HP, Cam is a Comp 280H hydraulic with 230 duration at .050 and .519 lift. Carb is a 750 vacuum secondary.
412 HP, Comp 280H hydraulic flat tappet cam, factory 735 CJ carburetor.
That's why I asked the question.
I suppose the ring pack, could account for the some of the HP, if they were different and also the quench?
Also, I found a C8AE-H head on the SW site that also flows, 266 CFM (w/smaller than CJ valves), done by a friend that I got to know after that.
Yes, there is more to it than cfm but, velocity can be tested and swirl. That would tell the story. Has there been any direct tests between cast iron a Edel heads of the same cfm rating?
Edel heads run, 258 (CJ60059), 250, 249 & 248 (6006), out of the box. There is also one listed at 270, (CJ60069). The C1AE, is 259, with just bowl work and 282 with bowl and port blend (I averaged the above C1 numbers). The C8AE-H, is ported using just a 2.055 intake and 1.558 EX and is 266. All at .600 lift. I'll ask Steve about it, next time I talk to him.
Ex was 205 on the C1, 174 on the C8, 174 to 183 on all the out of the box Edel's.