[Walt Fricke]

They will all fit, depending on what you are doing.

Note the CIS version has three round holes by the front (as installed in the car) left of center. These are to hold up a bellcrank assembly for the throttle. You also need a plastic extension to get the air over the oil cooler.

The middle ne should work on a CIS motor if you just made those holes. Same with the red early version, though you won't get as much cooling done to the oil, which is why Porsche added that ducting to the later motors.

I don't know about MFI, but carbs don't need an engine mounted bellcrank - it is mounted to the intake manifolds.

The early style is useful for race motors, where no engine oil cooler is used.