72 A/C 340 Demon fan/clutch space?

..stock rads were not even 2" thick...how thick is your aluminum rad.
i went with a 3 in alum and had to get rid of my clutch fan..it was too long.

You can see in the photos here. The aluminum radiator is only about 2 1/2" thick and is suppose to be a direct replacement. The space you see between the pulley face and the core is only just under 3". Other folks on here say they have 5". How could that be possible? Factory manual says I need a minimum of 3/4" between the blades and the radiator?? That only leaves a fan/clutch unit which is only about 2 1/4" combined? An I missing something here?? These cars just can't shrink. The motor bolts to thd Kframe. Why is this so tight??