Will it start if you spray carb cleaner into the intake, check fuel pressure
also, is this a Vortec or TB fuel injection?

I had a similar problem about a year ago on a Chrysler K car, and the
kind folks here reminded of the 3 basic things required to have an
engine start:

1 - Adequate fuel delivery
2 - Spark
3 - Proper timing

In my case, while I had spark and fuel delivery, my timing belt had
been chewed up by a damaged timing belt tensioner pulley. Took me a
while to tear the top half of the engine apart to verify, but once we
found it and repaired it, that car was good to go again.

Please be sure you check all of these things, ok?

Best wishes!