I know you're asking about electric.. but, another vote for a short clutch. I'm using a Jaguar fan clutch and factory blades.

On the front of my radiator, I installed 2 ~8" SPAL pusher fans.. they sit roughly behind the bumper. They do the job when the temp starts to creep up on hot days in traffic (67 Dart w/440).

If you find a powerful electric fan that will fit in there without moving radiators and engines around, please let us know what it is..