how to port swirl ports

the 308 w/2.02 valves flows the same as a 915/894 X/J head, the exhaust has a lil better 'few cfm' low/mid lift flow but in stock form still flows the 140's cfm that the old heads flow.
If you work the roof a lil and bowl of a 308 exhaust port, the exh numbers go up quite a bit.
The pushrod pinch of the 308 head sucks, but it does speed up air...so even tough the 308 w/2.02 int valves flows the same 225-230cfm that a J/X w/2.02's does...it could possibly help a hair in the velocity depot.

ultimately....ask urselves 'where are all the ported 308 heads that flow 280+cfm?'

Do you know anyone who has a pair?
How many of those heads have cracks?

I have a pair of them, they arent ported...yet....but im not sure i would go max effort with them , not at this point at least.

I say if 250/185 cfm int/exh is what ur looking for and those r the heads u happen to have....then ur good. It would take very lil work to get them there 'same work as old heads on int' and even less work than the old heads on the exh.
fwiw