HFfarms,
Congrats on scoring the manuals you found.
As far as a "conversion bible" existing, none in my experience to date. There are a couple of web sites that I have come across that do seem to provide some cross references between part numbers and current manufacturers info, but are not all-inclusive. They usually focus on the specific repair products involved (ie; bearings, seals, etc.). One that has proved at least a little useful is
https://www.finditparts.com/ . Although the site title says Heavy Duty truck and trailer parts, I have found several instances where I found current manufacturer part ID info (most often using the original GM numbers) that included down to the 1/2 ton truck size.
The search process, from ID of the 1st part number, superseding part number, and possible manufacturer cross reference of those (when no longer a good number) is time consuming, but often can be fruitful if your willing to put in the effort.
Dan
