Type numbers used by Alfa Romeo for identification. The number is located in the engine bay. Engine number is stamped on the crankcase close to the flywheel cover on exhaust side. The red spot shows an European engine. The US had the number on the intake side, yellow dots. This is a SPICA FI block
The engine head has an idetification mark in the front. Go here for more details. I have spent lots of time doing this chart, so please ask me first before you copy and use it. The information comes from the Fusi books.