what people might want.
I just replaced the 5.3 Vortec engine in my Avalanche with a Cadillac 6.0 to help with the heavy race trailer.
Does anyone need a 290 HP Gen III Chevy engine, maybe as a design mule for an LSX-powered race car?
Make me an offer, I can't refuse!

Yes, I think it would be a direct replacement for a 4.8, 5.3 or 6.0 GM engine in your truck, but it has 185,000 km on it already!  I didn't pull the heads and do a freshen-up because I wanted a bigger engine, and the price was about the same (a very good deal on the 6.0).
You could pull it apart and replace the piston/rings and bearings, and do a valve grind, then drop it in.  It does have a complete intake/fuel injection system, ring gear and exhaust manifolds.  $200 delivered?