As far as having them CNC ported Jeff at Modern Cylinder heads is the cats meao, the Bees knees and so on I have a set of his Eddy RPM CNC heads on my street motor, they pick the car up .3 ET and 4 MPH with no other changes over a set well massage big valve 906 heads The Eddy heads flowed 284 CFM at .600 at 28 inches on a Super Flow 600 bench before porting and Jeff made them flow 318 CFM on his bench at .600