I'm running the flex-a-lite 180 on a 70 Barracuda. Great unit, very durable and gets the job done. It was pretty easy to install too. IMO, it's a little pricey. I bought mine 2 years ago but I've seen the price climb pretty steadily since then.
In the latest Mopar Action Magazine issue, there is a write up on cooling systems including electric fans. You might find this helpful. Good luck.