Ferrari 308 ignition timing

You need to be at PM1-4 and be at the end of the cyl # 1 compression stroke (i.e., both cyl #1 valves need to be closed). Then select the closest spline position when mounting the distributor that has the distributor rotor pointing towards the red mark. That should be good enough to start the engine -- then the distributor housing is rotated at idle to get the final desired warm idle timing.

On a wet sump, determining both cyl #1 valves are closed at PM1-4 can be done by looking in the oil filler opening.

On a dry sump, you'll have to guess (if you didn't make some extra external marks yourself beforehand). Just try it at the PM1-4 mark -- if it won't start, return the crankshaft to PM1-4 with the distributor rotor pointing at the red mark, then remove the distributor and rotate the crankshaft exactly 1 revolution to PM 1-4 again. Then remount the distributor aligning the dist rotor to the red mark again and see if it will start.