Moto Guzzi V700, V7 Special, Ambassador, 850 GT, 850 GT California, Eldorado, and 850 California Police models
Dave Richardson's Guzziology provides the best instructions I've read for installing the distributor into the crankcase. For years I've avoided reproducing material from Guzziology because I do not want to infringe on sales of this fantastic reference book. If you do not own a copy of Guzziology, you should purchase a copy. Really. Riders of Moto Guzzis are extremely fortunate to have such a wealth of knowledge available to them - more so than many other very popular motorcycle brands. Support those who have gone to great lengths to bring this information to you. Buy Dave Richardson's Guzziology.
Because I keep getting asked for this information, here is a direct quote from Guzziology (version 5.2, chapter 6, page 17) on how to install the distributor on a Moto Guzzi V700, V7 Special, Ambassador, 850 GT, 850 GT California, Eldorado, or 850 California Police model.
Position the left-hand piston at the static timing mark (second notch from the left while facing the generator belt's crankshaft pulley) on the firing stroke (both valves completely shut). Remove the distributor's cap and rotor. Facing the right side of the engine, hold the distributor so that the externally mounted condenser is at about 9:00. Position the distributor shaft's upper notch at 5:00. Insert the distributor into the engine case. The notch should rotate to about 6:00. At this position, the points should just be opening, bumped open by the smaller of the two cam lobes on the distributor shaft. If not, loosen the 6 mm bolt holding the upper and lower distributor halves together and turn the top until the points are just opening. If the distributor's timing adjustment range isn't sufficient to attain this approximation of proper ignition timing, it will be necessary to remove the distributor and rotate the shaft one tooth to fall within the adjustment range.
If Dave asks me to remove this directly quoted material, I will happily do so.