How do you tell what liter your Slant 6 is?

Man ill tell u what it was harder than hell to get old water pump off, the bolts were so rusted , we had to cut then off, then bang them out. Then previous owner never had a clutch fan, so I tried but set up was a no go hits the radiator.
So my new question for you slant 6 owners do u currently run yours also without a clutch fan, or is this something I need to be concerned about? I have no over heating problems as of yet even before changing out the old water pump.
Thanks for your help