You need to be able to control cutter speed. You just can’t run them wide open all the time. I can use either but I prefer an air grinder.
It looks like your carbides have a pretty big diameter . When the ports are as small as what you are doing, and you need all the area you can get, I don’t use anything bigger than 1/2 inch and 3/8 most of the time.
A big corner radius in a perfect world is best. That head ain’t near perfect nor can it be made perfect. So corner radius need to be 1/2 or smaller. I’ve done some at 1/4 inch but that was a giant PITA for little return.
Look at the W2 port. It is to small for anything 340 inches and smaller over about 8000 RPM and as the displacement goes up the RPM at which the head is the limit goes down.
If you want to make the W2 enough cross section for stuff like that the option is to make them square. Another giant PITA.
You need to learn the relationship between cross section, displacement, RPM, Rod to stroke ratio (it matters), camshaft LSA, induction, exhaust, chassis, gearing and such.
