Electric fan in lieu of Flex Fan

I have an electric fan on the engine side of a stock 3 core radiator. I picked up at least 10 HP over the stock non-flex non-clutch fan, and the fuel economy I now get on the highway as compared to before is ridiculous. I picked up AT LEAST 15% fuel economy on the highway, probably closer to 20%. Even when it's 90* outside the car never gets hot. It's probably the best $100 I ever put into my Dart. I'll certainly be putting one on the Falcon this year.