Aluminum Heads

If you don’t already have the particulars, I’d get one of the 906’s off and cc the chamber, measure the deck clearance, calculate the compression and see if the 75cc E Street head might be a good option for you.

Lots of heads use powdered metal seats, shouldn’t really be any problem in that application.
All the hardware can be used that comes on the E streets with that cam.
The Mopar version comes with the same springs/retainers/locks/seals/spring cups as the RPM heads do.
If it matters for your exhaust, 75cc are angled plug, 84cc are straight plug.

E Streets are what I would use.