I typically work on these things in the afternoon, like starting around 3 pm. Besides Dynomation, I also have PipeMax for designing headers. Now PM requires a lot of measurements, like port length (PL) at the centerline and port volume. To measure PL you will need to use some 1/8" pin-stripping tape and lay it along the short side and long side. Then pulling out and lay them down in a straight line to measure, then take the average. Also need a actual Dyno output for best accuracy, but our simulation will work. Might have something tomorrow maybe. Be sure to page down, there is lots of info. http://maxracesoftware.com/PipeMaxPro400.htm Just depends on how far you want to take the theoretical.