Head Porting basics

What you have to remember is that no two heads are the same because of core shift...about 1 in 10 is a good candidate to try and go over 230 cfm.And not every port will flow the same if you get within 15 - 20 cfm your lucky.
I did those heads a few years back and I think the best port flowed just over 250 I seem to remember 238 (lowest) and 253 (best) cfm @600 with the bulk of flow happening between 350 and 600 and the ex flowed between 155 and 170 something.
I didn't want to get too thin as this was for a street car with an Engle solid roller RK48.It's a fairly fast lobe that sets the valve down kinda hard.