Thank you all for the replays. I'm new to car tuning but my understanding is that lt1 uses the optical sensor for cam position, with the 411 pcm and a stock tune from a Chevy express, l31, van it won't run well unless the cam sensor or optical sensor is disabled. Currently run a bin from a 2001 with it disabled, car runs good but I would like to try the bin I attached since it has better fan setting and speedometer is not completely off.