That very question has been debated and re-debated for years. I've read opinions of people who swear that pushers are the way to go, and other who swear that if your fans don't suck, then they suck. So to speak.
This means that nobody has proved without a doubt that either pushers or pullers are DRAMATICALLY superior to the other. Plenty of cars run just fine with pushers or pullers. There are some arguments pro and con for each.
I *believe* that consensus was that if you run with a shroud, then installing it in a pusher configuration partially obstructs the radiator, so the most efficient is to install a shroud, lay the radiator slightly forward, and install the fans behind. This insures that in traffic, when you need the fans the most, the fans "suck" air through the entire radiator.
The truth of the matter is that you'll probably be just fine with either configuration.
1985 DeTomaso Pantera GT5-S #9375
"Raising Pantera Awareness across Europe"