Grand Prix Legends .DAT File Format by P.A.Flack 1998
last revised 14/9/1998
 The .DAT files are used to group together many files into one.  The structure of the file is fairly straightforward as it consists of only three parts - a header; a directory; the files.  The header looks like this:
 
Bytes Values Notes
0-1 no. entries  Number of directory entries

Each directory entry looks like this:

Bytes Values Notes
0-1
2-5
6-9
10-22
23-26		 0x05 0x00
file size
file size
file name
file start		 always 0x05 0x00 for whatever reason
the size of the file, in 4byte, lsb first
the same (why???)
name of the file, padded with 0x00's
the starting position of the file within the DAT file

Then the files follow, consecutively.