will my stock ls1 o2 sensors survive pre-turbo?

[Chuck L.]

I thought o2 sensors would get increasingly inaccurate under positive pressure. I never could keep one together on my old 305 turbo conversion, the end of the sensor would just be burnt off lol {stub}

publishes charts showing the effects of pressure vs lambda readings.
As for your problem, I'd bet that the egts were "outta sight".
Restrictive exh systems also contribute to failures by creating excessively hi back pressure to boost ratios. More than 2:1, and you can create problems.
2 frequently found problems w/ O2 sensor failures in the turbo Buick are:
1. Blown headgaskets pushing antifreeze out the pipe, contaminating the sensor.
2. Race gas in hi % mix.

Here's a neat sensor test I ran across on U tube.
http://www.youtube.com/watch?v=1mb4VmDd0ao
Some other reading material...
http://www.normgrills.net/bcg/Injection.html