How do you tell what liter your Slant 6 is?

Thanks, yeah I was curious about that myself, because autozone tried to sell me one saying if you change the water pump u should change the clutch fan too, because they are in same area. So I thought I check first to make sure.
Also now in another situation, was changing out the valve gasket, and noticed one of the valve bolts was broke off into the motor. So now I have to try and figure out how to get bolt out and also placing a new one back in. Someone told me I would have to drill it out and then drill a new hole.
Does anyone have any recommendations on how or what procedure to attempt?
Thanks