Any thoughts on P4876310 large port commando head?

Found a great deal on some, what I believe to be, large port commando heads Mopar #P4876310. They look like an aluminum offset rocker W2 type head. I have tried to research these but can't find much on them. Any thoughts on making them flow around 300 cfm for a 408 street/strip 500+ hp setup? They look like an older casting, but if they work and flow than I may jump on them.

Thanks FABO!