When I was evaluating cooling fans and shrouds, I found that how the fans are wired makes a large difference. If you plug any fans into the stock wiring, they run.... at some rpm. If you direct-wire them to the battery, with only a relay or on/off switch so they get a full 13.8VDC, many fans will run noticeably faster, and fan air output is not linear. 15% more fan rpm can = 40-50% more cooling air. Before modifying the wiring, check at the present fan connections to see exactly what voltage is available now. Then hot-wire them and see what happens. You really need an anemometer to check airflow quantity but a piece of stiff paper in the breeze will show trends.
The reason this occurs may be because if you look under the flat bar that the hood hinges bolt to, you'll find a large factory-taped bundle of wiring. Inside are many FEET of extra wire folded into the bundle, some not hooked up. There are many extra connectors also, with a voltage drop at each one. We think the front wiring loom came from some large front engine car and the Pantera is much smaller. By stripping unneeded wires and connectors out of the bundle and re-taping, voltage to the headlights, fans and other up-front devices is improved.
Food for thought- you already know that sucker fans are more efficient at cooling than pusher fans, since a sucker shroud causes cooling air to move thru much more of the radiator core area. While most of us lay the rad' down for convenience, its quite possible to run shrouded sucker fans behind a stand-up radiator, even a larger one than stock. In any case, fans & shrouds are not needed above about 30 mph.