1. Keep the indexes if those are being used by your delete statement if not the delete is going to be terribly slow because of FTS on such big table.

2. If the no of rows remaining after delete the 71 million rows are much less than the rows being deleted THEN do this...
- Insert the rows (to be kept) into a table using create table as select.
- Truncate the original table.
- Insert the rows back into the original table using.. insert into select from...
- Rebuild the indexes.

3. If you do not have enough rollback space, do the delete operation in pieces and commit after every delete.

Sanjay