Hi Jim. The tall item is an oil breather "tower". It attaches to the block where the mechanical fuel pump noramlly goes. The alloy fitting at the top has 6 aluminum discs inside. The purpose of the tower is to help oil vapours condense and drain back into the block. Abarth made a short tower, and a tall one like in the photo.
The tank as you mentioned, is a "catch tank" to collect oil and vapours that have still not condensed back into liquid. The fitting on the top is a spin-on filter. There are two types of these tanks, the metal one for a TC and a plastic one for a TCR.
The 3rd Abarth item that goes with these is the "trident" fitting that hangs from the top of the engine compartment. One connect to the rocker cover, one to the tower, and one to the tank. I have seen a larger one, and a smaller one in photos.
You can still get replicas of these from BM. I recently bought a set of these 3 items on ebay. The photo you attached also shows some other later Abarth goodies like cooling header tank, and remote oil filter.
Regards,
Gil
