I do not remember what casting I used on that build. Any iron head can be ported to that level and more.
Even 304 small valve heads if larger valves are installed.
My street ported heads have a lot of work done to them. They have stock entrance size and no epoxy where race heads will have pushrod tubes, raised roof and a little more work in the runner and more time on the flow bench.
I am using 2.055/1.650 8mm Ferrea 8mm ID bronze guides and Ferrea 6000 valves from an LS1 application in all my iron heads now.
The heads for that build had 11/32. I am also using PAC racing dual springs, locks, retainers, and spring seat locators on all my heads.