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.

Just for your information there was a GM recall or customer satisfaction on those tailgate cables. If it was a recall they never expire. I would also have a dealer check for technical bulletins on oil consumption. If it is valve stems or seals it would be a lot less expensive than a overhaul. Do you get a puff of blue smoke when you start it after sitting overnight? That would be valve stems. If you want to put a new engine, GM sells re-manufactured engines with preety good warranty. 3 years I think. Also check out Rydell Powertrain. They offer 3 yr, unlimited mile warranty.