I would dearly love to get my hands on the service manuals for the 120hp lehman
The Grand Banks owner's forum http://www.grandbanksowners.com/
has a huge manuals section with everything from original GB owners manuals to all sorts of engine manuals, parts manuals, service manuals, generator manuals, you name it.
The FL120 operators and parts manuals are there along with BW Velvet Drive manuals and so on.
We were lucky in that our boat came with the manual(s) for every piece of equipment on board from the FL120 (both the Lehman and
Ford manuals plus the parts and shop overhaul manuals) to the BW transmission to the coffee maker, plus the boat's orignal American Marine owner's manual.* The only thing that didn't have a manual was the Onana MDJE generator but a member of the GB forum had an extra copy so he sent it to us.
I believe you have to join the GB forum to access the manuals section, but membership is free although they do request that you send an annual donation to help cover the cost of hosting and maintaining the forum.