Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_4327 ( "Heat Rank" real, "Lane" real, "Swimmer" text, "Country" text, "Time" real, "Overall Rank" text )

### Question ###
I want to know the highest heat rank for overall rank of t63 and time less than 25.47

### Accurate SQL ###

SELECT MAX("Heat Rank") FROM table_4327 WHERE "Overall Rank" = 't63' AND "Time" < '25.47'