water pump

[chevyhed53]

I'm sure this has been asked and answered many times, but here goes: I have a 400 small block with a long pump (photo) in my '56. I just put a new alternator belt on, and I noticed a very small amount of "play" or movement--just a tad--in the water pump pulley. It's not leaking, and it runs 180 degrees in the Florida weather, but I thought there should be no free play at all. Bearings going? Anything different about a pump for the 400 SB? Thanks!
Not sure why the photo is upside down. It's fine on my computer!