Short or Long Water Pump?

[My 72]

Does my 72, 402 BB have a short or long water pump? The engine is in many pieces so I can't measure the old pump cuz I don't know where it is.

Also, If I were to shop for a March Serpentine set up, am I limited to a short water pump? What would happen if I choose a set-up for a long water pump? What if any mods would I have to make?

I called and talked to one of their techs and he answered, "Hard to say".....Well, it ain't hard to figger out that don't help me any..........

Thanks in advance.....