electric fan puts more strain on the electrical system which affects spark.
put it this way. clutch fan, on a typical sr on the dyno, youre talking maaaaaybe a 2 hp. loss.
same car with a taurus single electrical fan, wired through relays, cost nearly 10hp. i have dyno charts to prove it somewhere on my computer at home.

theres a reason these cars come with clutch fans. its the best way to do it.
why do you also think some of the most well built schassis cars in the counrty still use clutch fans? and japan as well?

sure, some people use electrical fans with success, but one will never find its way onto my perfectly cool, even when being beaten on car.