Ok so if I have all this right:

1) the exhaust port is in the same location.
2) the head is overall taller than say an Eddy RPM.
3) The rocker shaft is moved up.
4) A Hughes Rocker lines up with the valve tip.
5) They have more potential than a fully ported Eddy RPM.
6) Sounds like you can use a 1.6 or 1.7 ratio rocker

Will 3/8" pushrods fit with higher ratio rocker and not require clearance ?

Thanks!