Pick-n-Pull Inventories
There are '77 and '78 320i's in the following Pick-n-Pull locations as of today:
Newark, CA
Stockton, CA
Antelope, CA
Sparks NV
Later 320i's with the 1.8L engine used a 1-piece manifold.
Hope that this helps. You can get on their home website and find where cars are for parts.