On an odd side note, I am experimenting with a slimline inside a factory shroud for my C53A. The shroud is metal like most turbo variant shrouds, versus the black plastic.
I had a spare that was a little rusty to work with. The aftermarket fan fits in directly, with only minor enlargement of the attachment holes in the shroud (x3), and a setup of deflective/aero type foam to seal the two units together so air is pulled in only through the fan assembly. I don't think this is the best option, but I have three slimline fans I posted about earlier that I get to play around with.
My Galant VR4 aluminum aftermarket radiator needs some cross member finagling because the welds for the four tabs, end up pushing the radiator body and subsequently the rad cap, likely right up into my hood.
So, there's a little fitment issue for my platform using the GVR4 50mm core setup from Ebay.
I have to drop my rad mounts and likely clearance my north/south cross member. So, stock type wide Colt rad and fans was my quick go to when I get this thing running again. It used to be a major pain to pull the radiator before, but with persistent work and redesign of my existing piping, I am hoping to speed up that process.
Some good info in this thread here.
IF you have room, consider the high end fans - with real published numbers. I have yet to comment on my thin wired/aftermarket fans, because they haven't so much as been spun up since I received them.
Oh, and I second the motion, that if you can't fit a 2/3 shroud (which is ideal for so many reasons), then get a fan that goes top to bottom, with genuine, high CFM count.