All post-1977, US Specification 308s were fitted with a convoluted emissions system to reduce unburnt fuel escaping into the atmosphere. This included an air pump, charcoal fuel canister, complex diverter valves, and other pressure regulation devices. This worked as well as expected and reduced the output of the engine, from 255hp to 240hp.

May 29th, 2021

• Previous to my ownership, the air pump system was removed from the car.
• In 2015, I had the headers removed and ceramic coated. As part of this effort, I welded the air injector holes. This functionally eliminates the air system entirely.
• Inspection of the system was no promising. General vacuum seems to be functioning incorrectly, with missing hoses and unplugged lines.

Airbox Analysis

It appears that the USA specification airbox has additional vacuum ports, most likely for additional fuel recapture. I believe the large port is for the crankcase breather hose. The additional line running down the center might go to the charcoal canister,

This part should be R&R. Airbox Restoration Journal here.

Remaining System Removal

• Removed seriously crispy vacuum lines
• Removed electronic valve
• Removed fuel spill over valve and relocated line to bottom of rear wheel well
• Examining the charcoal canister showed that someone had sealed the inlet with gasket maker at some point in the car's life.

Reassembly and Plugs

• The open lines attached to the carbs measured 6.46 mm in diameter.
• The open line coming off the carb body needs to be plugged. I would not be surprised if this was a source of the baby backfires that was happening in the engine.

Crankcase Breather Assembly