Need help choosing fans for my core

I bought this core because it was cheap and large but it's not exactly a parfect fit for fans, it measures in at 18cm high by 19cm wide, I only have room for fans to be pulling air through. So what size fans do you reckon I should use and how many?

There are a whole lot of 172mm fans out there that move one heckuva lot of air. Some are AC, some DC. Most are fairly expensive and noisy but I bet you can find the right combo for your heater core.

I have seen up to 300cfm 172mm fans available at 55dB down to slightly over 200cfm at 40dB.

"silence is golden" I don't want to have a windtunnel strapped to my pc, any other suggestions?

a 120mm with shroud should work fine.