Stock rear shock lenth

[clarks41]

Hi all, this is my first posting as a new member. I bought my first Ducati last Sunday. It needs a bit of work being a 1995 model, but for me it's half the fun of owning a motorcycle. I'd like to buy parts online for my bike, so if you know of a place that has good prices and ships fast let me know.
The new bike is a 1995 900 SS SP and the previous owner put on an adjustable lenth rear shock and cranked it way up in the back, to the point where the chain has worn through the top of the nylon chain runner because of the angle. Does anyone know what the stock lenth of the original shock was so I can set it there ? I'd need the center to center lenth. Thanks