I'm assembling a 445ci Windsor stroker for myself and just received my cylinder heads yesterday. I ordered these bare and had them shipped to Joe Craine for some head work. These are CNC ported from the factory, but Joe was able to squeeze a few more cfm out of them in the areas that would help me the most. I also had him mill them down to get 60cc chambers and clean up the
oil drainback holes.
These flow 335/263 at my .640" valve lift (interpolated from .600" and .650" lift numbers). They flow 343 @ .700". At higher lifts, exhaust flow is 78% of the intake flow.
I will assemble these with stiffer Comp dual springs (with titanium retainers) to help keep the valves where they're supposed to be with the hydraulic roller cam.
Keith Craft is doing the Dart Sportsman block for me and Harold Brookshire (used to work for Ultradyne cams and also designed the Voodoo cam series for Lunati) is grinding me a camshaft.