ozbear
I was wanted to fit them originally, but now i don't think so.
I didn't really notice the porosity of the castings, but i didn't really check them out that closely.
My motor is brand new and i know my late model rockers wont line up properly with the valve stems when in the liquid cooled heads.
I have had motors in the past where the rockers didn't line up properly and it was ok, but that was in motorcycles and they did wear adversely on the rocker surfaces. But you know what its like i don't think i want that in my plane.
There are things you can do to improve the cooling with the air cooled heads, so that's the way i will go i think.
Cheers