Pusher fans/puller fans

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Chances are you'll have plenty of cooling while you're moving even without a fan. The big issues are going to be when idling at lights or at shows. Watch the fan blade shape very carefully. Some fans are designed as pushers, some fans are effective when converted to pusher, and some just won't get the job done. A shroud is extremely important with a pusher to prevent air from spreading out and going around the rad instead of through it. Some fans have an outer ring that's part of the blade which works similar to a shroud to improve efficiency. This should not be considered a replacement for a shroud unless the fan can be safely placed within 1/4" or so of the rad. A/C condensers mounted underneath transit buses often have very good fan designs and good motors because there's very little natural airflow there.

There's a lot that goes into designing fans. It can be better to use two small fans rather than one large one if the large one's not designed right. Larger fans often have greater speeds at the tips and too much speed moves less air than expected. Ever notice how slowly those giant fans move in movies?? Based on experience trying to use generic aftermarket electric fans to replace the bus condenser fans, cheap stuff may look the same but OE tends to perform better. Search for "bus condenser fan pusher" and you'll probably find something useful.