Hello ; preparatory list is made for sc,st and pwd category students.One can get admission from preparatory course list on the following conditions :

1.The seats reserved for respective category are  vacant.

2. Candidates have not accepted a seat in the preparatory course earlier.

So if the reserved seats for sc category students remain vacant students like you from preparotory list get the chance.But sorry to say that with your rank in  this list it is too difficult to get admitted.

HOPE FOR GOOD!!!!