Depends on the cancellation done and which block did your RAC ticket entered when confirmed.
Like if you have RAC tickets for 2 pax and when your tickets confirms, 2 LB booked persons cancels, then your ticket will get those LB seats.
NB:This is my personal observation about how CRIS works about allotments of RAC/WL pax to Confirm mode other than cases when Railway personnel does allot manually for quotas.