906 heads ported?

Aussiemopars said
How can I tell if the '906 heads I have are ported? The metal seems a bit thin between the ports. Any measurements I can take?

View attachment 1715441595

If you can get decent aluminum heads where you are at somewhere near the cost of rebuilding and porting the 906s its a no brainer to go aluminum. 906 heads are crack prone , at least after porting and milling.