re: New truck spin-off, overhauling a GM motor.

There are very little differences between the 4.8 and 5.3 Vortec engines in those trucks. Both can benefit from a trick the F-body racers use on their LS engines. They replace the PCV valve with an oil catch can or valve cover breather. Half a qt over the course of ~5000 mi could easily be circulating from the heads into the intake through the PCV system, especially with the old ball style PCV valves.