they told me to get the biggest fans i could that would cover the radiator...so i searched summit and picked out just that...then i put the stock shroud over them.....on the IH i used the stock shroud and a single fan ..16in i believe...you can see how i did it in the IH build...
https://67-72chevytrucks.com/vboard/...750501&page=28 .. in post 690
you could always run the pump mounted fan ..if it lines up with the shroud...mine did not...thats why i went electric....also while searching ..ive been told the curved blade fans are quiter than the straight blade fans....i know on my 81 that when both fans are running ,and its idling ,they are pretty noisy