Best Piston Rings for the Magnum??

TrailBeast said
Poly? (probably Moly)
The OE 5.9 rings are Moly (chrome moly).
If you have new aftermarket pistons you should ask them for specifics on rings, like material, and end gap requirements for boost.

No, they are Moly faced. No such thing as a chrome moly ring. There are chrome faced rings and moly faced rings, but not both.