Puller only unless absolutely no way to fit in between the radiator and the engine.
Any radiator core not covered by the electric fan shroud should be masked on the engine side.
To add a bit...
Any electric fan shroud with large flat areas blocking the core should have flaps installed. They need to be top hinged so they lay flat and closed when stopped.
Air pushing through the radiator at speed will flip them open and allow air to get out. At low speed the electric fan will pull them closed and draw air through the radiator.
I can tell you that no matter the name on the box or the eleventy billion cfm marketing hype there is not an electric fan on the market drawing under 40 amps that can keep up with the massive volume of air slammed into a muscle-era car's grille at highway speed.
A tight shroud (read:pretty, slim, flat, close to the radiator core) will end up blocking air. If the store bought electric fan is powered up at speed it will not keep up with air flow and will become a 12 volt generator as the air flow overpowers it. Cutting flaps into the shroud will create a bypass that gives stacked up air an exit ramp.
People seem to forget that aerodynamics is at play between the radiator and shroud.
Look for OEM fans that fit your application. Dual fans can be handy for opening up some real estate in the center to allow a bit more room for the water pump.
