the ports under the rotor are .320" center to center . the rotor is .510" dia the crescents are the same as the ports . I'm going to build a 385cl cat which is as big as vario's 850 deere . I'm not sure these Robbe valves are big enough
the ports seem to small for the flow needed ( about 1 mm dia )
I may be making my own .
Stevie