I use an early Saab 99/900 n/a puller fan (swedish Electrolux, similar to some 122 wiper motors :-) mounted as a pusher in my 121. Works fine and after a few mods to the plastic mounting frame won't give you trouble with the restricted height in front of the radiator.

In my other car, two Saab 900 Turbo (old generation) fans are used as pullers. One of these Bosch units probably would pe a perfect fit even in the 122, small diameter and not that deep. And just like Evan, I like Bosch parts - quality is great and they are just right in a Volvo.

As for CFM, I don't think you should worry to much. Remember that the most difficult cooling situation is city driving, when the original fan rotates at very low speed and there is no help from car speed through air. The original design without a shroud wasn't particulary efficient, either. "Any" electric fan will move more CFM than this setup at idle/low rpms.

What you should remember, though, is that high idle loads are a nightmare with the old 30A DC generator (-1966). Consider an upgrade with a 35/55A alternator if your car has got this system.

Martin
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'65 121, '73 165