We had a set on the flowbench for about 2 hours tonight. The customer spent $700 for the pair assembled.
First off, the bad part. The exhaust on this head is horrible, from low to high lift. Extremely turbulent, lots of dips on the low lift below .500, just a poor design and just doesn't work. The whole design is a mess.
The as delivered valves are an unknown manufacturer and the quality of the cuts would lend me to believe you'd be better off buying them bare. The springs were speced for a hyd. camshaft and can not take anything more than a .480 lift cam. They speced as indicated in the literature, about 110 on the seat. The delivered seals are cheap. If your not careful when you take them off they will tear.
The intake ports were very slow to respond on low lift, a VERY lazy port up to .450 to .500. One port did peak around 250 CFM and did hold it through .650 but at .400 it only flowed about 200 cfm. Not too peppy since your limited to a .480 lift cam with the hyd springs.
This head needs chamber work, lots of bowl work and a good valve job to get it working in the low range on the intake. The exhaust, I think you just start working it and see where you end up. That needs lots of work. The basis design, square port, is just poor compared to other castings.
I think the head, with around $800 in porting, will easily flow over 300 cfm and the low lift numbers would be in the 245 or better range at .400, which would be a very good port for a 23 degree head. The exhaust, I'd have to show it to the porter for him to see what he thought. I think his first reaction would be EWWW. So, to get a great head buy it bare for $600, fully port and install REV or Ferrea valves, good springs, seals and retainers and for about $1600 or so you'll have a killer head, maybe.
For about the same amount of money you can buy a set of Vortecs and have better flow through .500. Or for a little over a grand have a set of E-Tec's by Edelbrock that have good components and tower over these, especially on the exhaust.
The intake port location is raised slightly, similar to a vortec. The customer indicated the seller recommended a Vic Jr intake, which will need to be matched to the intake.