You will likely need new brackets because the axles are shorter, thus the disc won't line up with the old bracket anymore. Probably be about 3/4's inward. Remember the bracket is secured to the housing, so when you pull the axle in, it doesn't move.
This is why i used 95 cobra discs+calipers, and used stock length axles and NRC brackets. I could always add spacers if necessay.
But, i had a head start on most internet people, since my car has had 5 lug drums since 1990, so i knew to keep the stock length.