Ok I have a 2001 monte Carlo ss 3.8 liter motor whice I replace recently with a 2003 3.8 liter but this one I put in was a supercharge motor so it's slightly different from the regular 3.8 now since I have made the switch my car only crank over but no start everything is properly hook up I thing could it be I have to reset my ecu? Or is it something I'm not doing correctly please help me out with this one anybody

 

What did you do about the pcm tune? The two engines have different map sensors / maf sensors / calibration.

If you properly loaded the SC tune, check for fuel and spark as usual. Likely missing one or more of those if it's not giving any sign of life while cranking.