[6pack] Electric cooling fan: pusher or puller?

[Henri Lefebvre]

What is the preference for an electric cooling fan? Pusher or Puller?
As a Pusher, there seems to be easier mounting points in front of the
rad, but the fan and housing will reduce the free flow of air to the
rad.
As a Puller the free air flow is better but mounting is less
convenient and the mechanical fan extension must be replaced.

I would appreciate comments and opinions, thank oyu,

Henri
75 TR6, triple webers