I found a rrent with MMC engine workshops manuals globally since 1990, including 4, 6 and F series engines.
Didn't know there was both a E-W and W-E version of the 6G74.

The whole thing comes to about 700mb zipped.
EDIT: cant post the 6G74 section, as its too large for attachments.
EDIT2: The rrent link can be found at:

http://thepiratebay.org/torrent/3548036/Mitsubishi_Engines_and_Transmissions_Every_model_s ince_1990_Work