Has anyone installed a Flex-a-lite fan(fan only, not electric setup) on their truck? Do they save ya any mpg or any gain of hp?

My dad always used to put them on our Buicks (57 on up). We towed campers with them. He said they help a little, plus better cooling. Also he had me hold the Flex Fan vs the stock fan and said the lighter weight makes a big difference. He was an excellent mechanic so I believe him.

Just wondering if anyone has any experience with these fans lately.

Thanks,