So a friend of mine is adding one to the front of the radiator on his old Pontiac. To change it to a pusher the instructions say to reverse the fan blade and also the polarity of the supply. It mounts through the core with special plastic retainers.
That makes good sense to me. You will be reversing direction, and retaining the proper orientation of the curves in the blades. Having said that, the blades on that setup must be specifically designed to accomplish this swap. It wouldn't work with a blade designed like an original fan or a standard flex fan.
