water pump pullies?

I think that or I suspect that my water pump is maybe being over turned. Mainly when I get on it hard the temp will go up but then come back down a few seconds after I just start to cruise. I have a mark 8 fan with a fluidyne raditor. I havent check the cap yet, Was just going to buy one of those anyway. I notice on my recipts that I the pervious owner gave me, one of them saids "water pump pully" Now I dont know if they went with underdrive or "stock"

My question is what is the stock size?

if it moves the water to fast, it can be cool? correct? the motor is fine. Might be a timing issue. but havent addressed that yet.