You are right. 16 bit block numbers 24 bit file size for V6.
On Jun 1, 2020, at 8:14 PM, Noel Chiappa
From: Ronald Natalie
The V6 file system was limited to 2^24 blocks
No, 2^16; from filsys.h:
int s_fsize; /* size in blocks of entire volume */
and of course on an -11 an int is 16 bits.
Maybe you're thinking of the file size, which was 2^24 bytes (max).