Ported X head pics

Absolutely nothing but cleaning on the exhaust port.
and leave the floor at the header area As Cast.
You really should remove your attention from the exhaust.

"Just my opinion" BUT you get the exhaust flowing better, it will flow better in revers aka, it will run up the intake valve when both are open. Steal all your bottom end and Ruin The low end torque, just as if you would have put a big lumpy cam in it.
You haven't changed it much but spend any more time equalizing all the exhaust ports aka matching them. The two "center" exhaust port have a different shape then the out side one. just something to keep in mind.