Looking at newer post, it seems like these were 43xx
or something like
 that.  I recall we had a machine the wasn't called a mini and that
 number ( as I recall ) was a 3081. It was quite big. 
The 4331 which I helped move into the computer center occupied the
floorspace of a single desk, but was a little bit taller, and was an
air-cooled system.  I believe the 4341 which later replaced it was the
same size.  They were quite heavy, size notwithstanding. :)
The 4381s I met later were double-wide 6' rack cabinets, similar in size
to 3380 dasd cabs, but still air cooled.
De