It’s a 12 valve. You must be correct about the turbo. I can feel the power come on as the turbo spools up in 4th and 5th. The truck really accelerates.
The 5.9 is an amazing engine. High performance fab shops machine the entire 5.9L engine out of billet now for pullers and drag racers. They are very durable with 6 in a row. No opposing forces.
If you ever have the need, consider a turbo with 1.5 to 2x the CFM of air it will pump.