Need help identifying SBM cast iron head
It's not much help on an assembled, running motor, but late SBM heads have the casting number on the underside of the head on an intake runner.
![1720711288066.png 1720711288066.png](https://www.forabodiesonly.com/mopar/attachments/1720711288066-png.1716274693/)
Maybe you can pop off a valve cover and sneak a peek of it with a borescope.