which head to modify?

does anyone know which 16v head is better to modify 9a/6a or kr???

ive "read" that on the kr the inlet ports are bigger and the exhaust ports are small
but....
on the 9a heads the inlet ports are smaller and the exhaust ports are bigger..

also is there a water/oil passageway on the 9a heads which restrict them from porting.polishing too much??

so does anyway have any ideas?

cheers

 

i thought they were all pretty much the same once they have had some work done on them...

 

thats what i thought but thats only true if you get both ports worked on though..

 

anyone?

 

More meat on the 6A/9A head to be worked on, so you can take it out further if you need......... I had a pic somewhere but I can't find it.........

 

thats the 050s they are more meatty

the 020 and 027s have the less metal