Thats a baby cam, even for a stock LT1, I am with the others here. I think you need to re-check the valve lash...
Also, have you had any programing done??? Is it backfiring out the exhaust or the intake? You might be getting a little bit of reversion in the exhaust caused by the camshaft, which is screweing with the oxigen sensor, and you could be just in need of more/some tuning.
Take 'er easy,
Erik
