Ordered a new power steering pump off summit, its a rebuilt one but dose not accept my old stock pulley. The stock pulley is to small to slip onto the pump. Also the stock pump has a raised fin that the pully slips over so it cant spin. My new one dose not, cant i just get a new pully? how do i know it will fit?

 

You got a newer (76-later) pump that uses a press-fit pulley. The 75-earlier pumps are splined.
I haven't found a suitable two v-belt pulley yet, but also haven't searched very hard. The one belt pulleys are somewhat common.

You can switch to a splined pump. At least I'm pretty sure Summit also offers them. If you stick with the press-fit, note that you need to use the correct tool to install the pulley. Hammering on it will destroy the pump.

 

Actually, they use a keyway, not splines.