On the first one methinks the intake is 180 degrees out - the air intake is usually on the passenger side for that engine. The second one looks like a small block Chevy thinly disguised as a Buick. The third one well let's just say that's the way it should have been from the factory.
It appears that the intake is not reversed... it's just an entire fullsize car engine.
At least, I don't think Fox Mustangs had the A/C compressor way up there on the passenger side. Foxes ran the airbox on the passenger side, fullsizes ran it on the driver's side. Plus, the car looks to be an '83 or so, too early to have been a factory port EFI car.
I wish I took more photos of the BMW. It was extremely nicely done. Maybe it will be back next week? All photos taken at the cruise-in on 42 just south of 303. I forget the name of the diner that hosts, but you'll be driving down 42 on a fine Saturday afternoon and pass some strip malls and all of a sudden there's one or two hundred musclecars, street rods, lowriders, etc. on the left hand side.
Actually, the red Mustang could be an '85 or '86 ('83-84 had a bit of an eggcrate grill). The '85 comes originally carbureted, where the '86 is injected. The regular v-belt to the alternator tells it was an '85, where the injected cars had a serpentine set up...I'm going with a carburetor conversion.