does anyone know what year this hemi is?

doesn't 51-53 have two waterpumps? thank you

 

Might want to post an intro before jumping on here, they will jump you for it.
As far as I know all Hemi's have one pump. Your pics don't show it but is your bellhousing part of the block? If it is the you do have an the early Hemi.

 

Also, the numbers stamped on the top, front of the block will tell you what you need to know.

 

Should be just one water pump for all the hemi's.

However, that engine has a "wet" intake, and no water crossover ports at the front of the heads. That would lead me to believe that the heads are the '51-'53 variety, since later heads had water ports in the front for the crossover. But, the engine could still be something other than '51-53. Still, if I were a betting man I'd say it was a '51-53 331, or possibly a slightly later truck engine.

The use code stamped on the rail between the valley cover and the water pump should tell you all you need to know, as squirrel already pointed out.