My problem with burnt valves WILL happen to you too!
The EGRless 3800 engine was/is notorious for burning out valves since the exhaust is hotter then a 3800 with an EGR valve!
That is why GM returned in 94 by putting on EGR valves again!
At first GM emission tested these 3800'* w/o EGR valves & they passed emissions so no need to put EGR'* on!
Later when GM noticed an increase in burnt valves on these EGRless engines they (GM) rethought that decision!
I've been told that is NORMAL for these engines at around 150,000 KM mark! :( The good news is that you can just replace the valves & install the head w/o doing the bottom end.
Just some FYI for yah!