And they just pull the pattern out of space that the cnc is designed from. I’ve never had a cnc’d head in my hands that I couldn’t make better. No matter what someone has to get dirty to get the job done.
Heard that argument years ago from a guy I know who does heads. He now has a CNC machine..
He said porting heads the old way was like sweeping a floor with tooth brush and rolling around in the mess while your doing it. The machine does the bulk of the work quicker, has a database of "what works", he's able to map other peoples work for comparison and all he does is a tidy up, if needed.
Look at CNC hones, way quicker turn around time, less block heating, better surface finish and a 16 year old kid could use one.