brand new comp XE268 is 21 13/16 inches long from end of bearing to end of pins.
Can you jack up the front of the engine and this might help to get more length between motor and condensor core?
I have a 1980 L48 and was able to put a cam in. Radiator had to come out but I was able to get it in with AC loosened. You can move it around enough to get the cam in.