Setting ignition timing - Single Distributor

You don't have a copy of the 155/78 OM covering late euro carbed 308? If not, you should get one

6 deg BTDC at warm 1000 RPM idle

The timing marks are on the edge of the flywheel (so you need to remove the small flywheel cover approximately under the oil filter), but it is often necessary to first find the flywheel marks without the engine running and then make corresponding larger marks using some nail polish on the pressure plate cover -- useful to use two different color -- one for the PM1-4 (TDC) mark and another for the 6 deg BTDC mark.

Here's an example on a US version 308 (which has 3 flywheel marks in that area: 7 deg BTDC, PM1-4, and 3 deg ATDC) where the person used a long paint mark on the pressure plate housing for PM1-4 and shorter paint marks for the others:
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This link will get you a pdf copy of the 155/78 OM:

https://www.dropbox.com/s/fgpfc3cehs68vy3/MUM_308GtbGts 155_78.pdf?dl=0

but, IMO, you should really get a print copy. They aren't super-expensive -- I'd try eurospares UK, Maranello Concessionaires, or any of the usual F part suppliers. There's also this other thing called the internet where you can search on "Ferrari 155/78" and get links like this:

https://www.ferrarichat.com/forum/threads/ferrari-owners-manuals-for-328-308-mondial-208.511604/

Yes, per 155/78, there should be another flywheel mark at around 33~34 deg BTDC for checking at 5000 RPM.

 

Or use dial back timing light, and set the light at what degrees advance you want to verify, that will let you use the single TDC mark as your reference for verifying the advance curve.

The digital readout timing lights show engine RPM also. Makes it real simple.

Doug