I still have an XP version running (although am pretty sure it is using NTFS) - the maximum size that I seem to see for any of the block files is 134 MB.

They are named as such:

blk00000.dat
blk00001.dat
blk00002.dat
...

The "reverse" files are named as such:

rev00000.dat
rev00001.dat
rev00002.dat
...

(and are much smaller)