Chapman seems to be the premier CNC porting shop at this stage, and are currently charging premier prices . I haven't had the pleasure of witnessing the machining service for myself, but have done alot of 3D Aerospace machining in the past. Now if these heads were one of the first sets of heads to come out of Chapmans shop, I could understand the high cost. As we know , to do these heads, specialized machinery is required, which is generally not found in your everyday engineering jobbing shop, so the cost of the initial purchase of their 5 Axis, or horizontal Machining center with a 4th axis, or whatever they are using would be factored into their intitial cost. Tooling would be another, specialized carbide ball end cutters etc. Their 3D software program, depending on what's being used, the software could cost anywhere from a few thousand to over $10000, I am really only familar with SurfCAM and UniGraphics, Uni Graphics as a package in Australia cost a tad over $20000 Aud. Chapman have been doing CNC head porting for some time now, and were really one of the few companies doing it, so I guess it still understandable their prices are still high. When some more competition in the market comes about, then I would expect to see their prices come down. I have seen a couple different Chapman heads, both being Edelbrock Ford heads, and their work is quite nice. I do agree with Dwayne, there wouldn't be a huge amount of time in them, the CNC ported stuff I have seen usually has a 0.040"-0.060" step over, which isn't that tight really. Most general finishing on 3D stuff I have done has been 0.5mm, and 0.1mm on the small fine stuff . So depending on feed rates, spindle speeds etc, I would guess 4-5 hours to be about right with a roughing and finishing cut. Just to finish, a friend of mine has a set of Chevy heads that Dart CNC ported for him, they are their new 11* big chiefs of something like that, the CNC port job was around $2500US on the pair, but these things flow just under 550cfm @ 0.900" Something like that I would expect to pay that kind of $$$, looks like MP got it wrong again, lol
AL...