The 930 LSD is compatible with the 915 series of gearbox, however you must use the correct flanges. This is dependant on year and other factors, so there are exceptions to this statement.
The 915 "ring" which you refered to is nothing like the 930 ring and pinion. These final drives and gear sets are comepletely different and DO NOT interchange. You wouldn't want the 915 garbage in there anyway.
I have 930 LSD's in stock and have replacement parts for the 930 gearbox. Which I must say is an excellent choice for a 40 replica. They are very well designed strong gearboxes with very acceptable V8 ratios from the factory, congratualtions on finding one. You may contact me for more information on gears and replacement parts. I would be happy to help get it back to operating condition.
