There is no reason you cant run the AC. I did a 440 in a 74 dart ac car. I never got the ac finished because I didnt have all the small block ac parts and had to seel when I had a kid. But mounting the later sanden compressors isnt that hard. It is the big old ones ,I think York, that look like a v style engine that take a lot of space. Basically an F body fits like a b body but no torsion bars in the way.
Now my Bigger Ac blower motor hit my MT valve covers.so I custom made a blower motor from a fan motor,some aluminum and a universal squirrel cage. All because the MT valve covers were way too cool to replace with factory tins.
If I ever get a hold of one of those f body wags that isn't junk it will be a 440 for sure.
I wonder if the old cross rams would fit?