Since you already have the la front end on the engine, it is effectively the same as an la.
I just put factory air salvaged out of another car in my 69 cuda, so I did it the hard way. Since mine has a 360 swapped in, nothing much was stock. It was an ordeal getting the belts all set up. mine had power steering which complicates things. Dodge V8 trucks, which are very similar and plentiful in junkyards, are a good source of parts. Since you don’t have power steering or a mechanical fan yours should be easy. Some aftermarket intake manifolds are not compatible with a/c due to missing mounting features.
The aftermarket a/c guys sell brackets a lot of applications, but all their stuff is pricey.